New Zealand Thecate Hydroids Part II.—Families Lafoeidae, Lineolariidae, Haleciidae and Syntheciidae

Transactions and Proceedings of the Royal Society of New Zealand, Volume 85, 1957-58, Page 301

New Zealand Thecate Hydroids Part II.—Families Lafoeidae, Lineolariidae, Haleciidae and Syntheciidae By Patricia M. Ralph [Received by the Editor, July 18, 1957.] Abstract Records a total of 31 species of New Zealand thecate hydroids from the Lafoeidae (14 species), Lineolariidae (1 species); Haleciidae (11 species) and Syntheciidae (5 species); describes, keys and discusses the systematic status of the New Zealand species of these families resulting in the following changes: F. Lafoeidae, genus Perisiphonia Allman, 1888, a synonym of Cryptolaria Busk, 1857: F. Haleciidae, Halecium flexile Allman, 1888, and Halecium parvulum Bale, 1888, synonyms of Halecium delicatulum Coughtrey, 1876; Ophiodissa armata Totton, 1930, a synonym of Hydrodendron armata (Totton, 1930); and Halecium fraseri, nom. nov. for “Halecium flexile” as recognised by Fraser (1944) but not known from New Zealand waters: F. Syntheciidae, Synthecium ramosum Allman, 1885, a synonym of Synthecium elegans Allman, 1872; forma elegans, and colonies of S. elegans with short erect stems and hydrothecae about 0.5 mm in total length recognised as S. elegans forma subventricosum Bale: Synthecium tottoni nom nov. for Synthecium robustum Totton, 1930. Cryptolaria exserta Busk, 1858, Halecium beanii (Johnston, 1838), Halecium (?) tenellum Hincks, 1861, Halecium sessile Norman, 1866, Halecium fragile Hodgson, 1950 and Hydrodendron caciniformis (Ritchie, 1907) are new records from New Zealand. Introduction This paper continues the revision of thecate hydroids commenced in 1957 with the Campanulariidae and Campanulinidae. Collection from all round the New Zealand coast has made available a much greater amount of hydroid material than has previously been the case, and thereby made it possible to attempt for the first time what is hoped will be a comprehensive revision of the New Zealand hydroid fauna. The Sertulariidae, the largest family of New Zealand thecate hydroids, are planned for revision next, and then the Plumulariidae, generally considered the most specialised family of thecates as its members possess hydrothecae confined to one side of the branch (hydrocladium) and various types of nematothecae. The families Lafoeidae, Haleciidae, Lineolariidae and Syntheciidae are here grouped together for three reasons. Firstly, most species in the Lafoeidae, Lineolariidae and Syntheciidae have the hydrotheca attached in part to the stem, or hydrorhiza; secondly, species of all four families possess an hydrotheca without an operculum and with an entire margin; and thirdly, the majority of their species are sublittoral in habitat. These characters contrast on the one hand with the Campanulariidae and Campanulinidae in which the majority of species have the hydrotheca held free from the stem on a stalk, and are intertidal in habitat, and on the other hand, with the Sertulariidae in which with rare exceptions the hydrotheca possesses an operculum and a toothed margin. Most of the material in the present collection referred to in this paper has been dredged from Cook Strait within the last three years, but it also includes specimens from Otago, Chatham Island, Bay of Plenty and Auckland areas. Most species have been taken from 40 to 200 fathoms, but the “Challenger” Expedition took the lafoeids Acrytptolaria gracilis (Allman) and Cryptolaria pectinata (Allman) in 700 fathoms off East Cape, North Island. this is the greatest depth from which a species

of the families described here have been taken in our waters. Several New Zealand haleciids are, however, best known from the intertidal region. With the steady increase in recent years of dredging round the New Zealand coast the additional material obtained has allowed a decision to be made on the status of a genus and on several species known previously from a small amount of material and often not showing a full range of variation. For example, the status of the genus Perisiphonia and the species Halecium delicatulum, Synthecium elegans and Synthecium ramosum, etc., have been determined. Further, the present material has indicated various localities from where more dredging would undoubtedly facilitate a decision on the status of other species which may have been misidentified because only a few infertile specimens from one locality are known—e.g., the status of Hebella cylindrica, known only from the Bay of Islands, and closely resembling some growth forms known from New Zealand of the cosmopolitan Hebella calcarata: and Synthecium longithecum, known from infertile material from one locality and very similar in stem characters to S. elegans forma elegans. The family Lafoeiidae is perhaps the least well known of the families described in the paper. Four of the 14 recorded species are known to me only from the literature, one from a fragment of the type specimen, and three from colonies from one locality, but the other six are better known and there is abundant material of Cryptolaria prima and Hebella calcarata both from North and South Island areas. Several species of this family have, however, been described from inadequate material and possibly misidentified. The lafoeids are recognised as preferring warm water conditions, and it is interesting to note that the majority of species of this family in New Zealand are known from North Island and Chatham Island localities—that is, within the range of the Subtropical Convergence. Nevertheless, three species, the cosmopolitan Hebella calcarata, Reticularia serrata, better known from North American waters, and Cryptolaria prima, a unique New Zealand species, have all been taken from South Island localities. Species of the Lineolariidae. Haleciidae and Syntheciidae are better known than those of the Lafoeidae in New Zealand, and five species of halecids are new records for our waters. The only species of halecid previously recorded and not represented in the present collection is Hemitheca intermedia Hilgendorf, 1898, another unique New Zealand species of puzzling systematic status, in which the hydrothecae are confined to the branches. Two of the five New Zealand species of Syntheciidae are known to me only from the literature, but there is a possibility that one of these, S. longithecum, is misidentified and a synonym of S. elegans Allman forma elegans. Measurements of size, slide number and figures given for the species in the present paper are derived from the author's personal collection of thecate hydroids unless otherwise stated. This collection is lodged with the Zoology Department, Victoria University of Wellington. Where species have many synonyms, only an abbreviated list is given here, but a reference source for fuller synonymy is included. Acknowledgments The author wishes to thank Professor L. R. Richardson for his encouragement and helpful advice; the Governors of the “Musgrave Fund,” Cambridge University, England, for financial assistance which greatly facilitated field collection; Dr. W. J. Rees and Captain Knyvett Totton, of the British Museum (Natural History), for literature and for arranging the loan of New Zealand hydroid material lodged with the museum; Dr. C. W. Brazenor, National Museum, Melbourne, for the loan of specimens; Dr. P. L. Kramp, Universitetets Museum, Copenhagen, and Dr. F. S. Russell, Marine Biological Station, Plymouth, England, and Dr. Maurice Blackburn, University of Hawaii, for literature; the library staff of this University, and Miss M. Wood, Secretary of the Royal Society of New Zealand, for helpful cooperation in obtaining literature; the Directors of the Dominion Museum, Wellington, the Auckland Institute and Museum, the Canterbury Museum, Christchurch, and.

the Otago Museum, Dunedin, for loan of their hydroid collections; Miss Barbara Dew, Marine Biological Laboratory, Cronulla, New South Wales, Miss Pamela Pennycuik, University of Queensland, Brisbane, Dr. Elizabeth J. Batham, Marine Biological Station, Portobello, Dunedin, Mr. G. Knox and Mrs. K. Kiddle, Mrs. S. Rind, Canterbury University, Christchurch, Mr. R. Kulka and Mr. C. Trevarthen, Auckland University, Auckland, Mr. W. H. Dawbin and Mr. J. Garrick, Victoria University, Wellington, and to many other friends who from time to time have given valuable help in collecting material. Family Lafoeidae Hincks, 1868 Colonies stolonal or sympodial; hydrothecae tubular, without operculum, stalked or sessile, and at times partly adnate to the stolon or stem; hydrotheca with or without a diaphragm; hydranth with conical proboscis; gonothecae either aggregated as a scapus or coppinia, or occurring singly; reproductive zooid producing free-medusae or a fixed sporosac. Most of the well known genera of this family are recorded from New Zealand—viz., g. Hebella, g. Lafoea, g. Acryptolaria, g. Reticularia and g. Zygophylax. In general these are represented by their cosmopolitan species, but the two species of Zygophylax are rare. Sufficient material of the g. Cryptolaria Busk, 1857, formerly confused with Acryptolaria Norman, 1875 (see Totton, 1930) and Perisiphonia Allman, 1888, has come to hand to enable a firm decision to be made on the status of the g. Perisiphonia. This material shows Perisiphonia as a synonym of Cryptolaria. Except for species of the genera Hebella and Reticularia which are stolonal in habit, species of the other genera of the F. Lafoeidae in New Zealand have polysiphonic erect stems. Cryptolaria prima is the tallest and most conspicuous, with stems up to 24.0 cm in length. All the polysiphonic species support an epizoan population of other hydroids, polychaete worms, sponges, polyzoa, foraminifera, etc. Twelve species of the family were previously recorded from New Zealand—namely, Acryptolaria gracilis (Allman, 1888); Acryptolaria conferta (Allman, 1877) var. australis (Ritchie, 1911); Acryptolaria minima Totton, 1930; Cryptolaria prima Busk, 1857; Filellum serratum (Clarke, 1879); Hebella calcarata (L. Agassiz, 1862); Hebella cylindrica (von Lendenfeld, 1885); Hebella corrugata (Thornely, 1904); Lafoea dumosa (Fleming, 1820); Perisiphonia pectinata Allman, 1888; Zygophylax sibogae Billard, 1918; and Zygophylax unilateralis Totton, 1930. As noted above, the present study has resulted in the following changes: the genus Perisiphonia Allman, 1888, a synonym of Cryptolaria Busk, 1857; and following Totton (1930), the g. Filellum Hincks, 1868, a synonym of Reticularia Wyville Thomson, 1853. Also, Cryptolaria exserta Busk, 1858, is recorded from New Zealand for the first time in this paper. Key to the Genera of the Family Lafoeidae in New Zealand The characters of the hydrotheca and the manner in which it is attached to the stolon or erect stem are used here as the primary basis for separation into genera. Two distinct groups can be demonstrated; firstly, that which could be called the Hebella-Lafoea-Zygophylax group, and secondly the Reticularia-Acryptolaria-Cryptolaria group. Both groups contain genera in which the colonies are stolonal in habit and others in which the erect stem is polysiphonic and may be large and coarse. In the Hebella group the hydrothecae of a colony stolonal in habit arise from a distinct pedicel, even though in some cases this is very short, and this pedicel holds the hydrotheca free and in general upright from the stolon. Hydrothecae and pedicels free from their originating structure are also present in the more complicated polysiphonic colonies of the genera Lafoea and Zygophylax (Fig. 2, a and e). In contrast, the hydrothecae of genera of the Reticularia group are attached for at least a portion of their length to the stolon or erect stem and the hydrothecae of genera with polysiphonic stems in this group become more or less immersed in the accessory tubes making up the compound stem and main branches. Nematothecae are found in the species of both groups.

1 (6) Hydrothecae with distinct pedicel, of variable length, and which may be very short; pedicels hold hydrothecae free from the stolon or stem, i.e., hydrothecae are not adherent: gonothecae simple, or aggregated into a scapus or coppinia. 2 (3) Colony stolonal, hydrothecal pedicel arising directly from the stolon, never polysiphonic; hydrothecae usually with distinct diaphragm; gonothecae also pedicellate, reproductive zooids producing free medusae. Hebella Allman, 1888 3 (2) Colony with branched polysiphonic erect stems. 4 (5) Hydrothecae without diaphragm; no nematothecae: gonothecae usually fused together forming a coppinia. Lafoea Lamouroux, 1821 5 (4) Hydrotheca with diaphragm, and carried on a pedicel which arises from an apophysis of the axial tube; usually a distinct joint between the base of the pedicel and the apophysis (Fig. 2, f); nematothecae usually present: gonothecae either separate (rare) or fused together, or some fused and some separate; tubular protective structures often present when the gonothecae are fixed, forming a coppinia. Zygophylax Quelch, 1885 6 (1) Hydrothecae without a pedicel, or arising directly from an apophysis of the axial tube of a polysiphonic stem (Fig. 3, a and b), (apophysis often described as a pedicel); hydrothecae adherent in some degree to the stem or stolon; a well marked oblique joint may be present between the apophysis and the base of the hydrotheca, and this joint often described as a diaphragm (Fig. 6, b); gonothecae aggregated into scapus or coppinia; reproductive zooids producing a fixed sporosac. 7 (8) Colony stolonal, hydrothecae partly adnate to stolon, free portion curved upwards: gonothecae aggregated into a coppinia. Reticularia Wyville Thomson, 1853 8 (7) Colony with branched polysiphonic erect stems; axial tube carrying the hydrothecae and the hydrothecae of the main stem and larger branches usually more or less covered by a peripheral bundle of accessory tubules. 9 (10) No oblique joint between the base of the hydrotheca and the apophysis of the axial tube on which the hydrotheca is carried, and the base of the hydrotheca frequently passes into the axial tube without any change in diameter, but a constriction or a row of puncta may mark the base of the hydrotheca proper from the apophysis of the axial tube (Fig. 4, a); stems without nematothecae; gonothecae usually loosely aggregated, forming a scapus. Acryptolaria Norman, 1875 10 (9) Distinct, often thick oblique joint (Fig. 6, b) between the base of the hydrotheca and the apophysis of the axial tube on which the hydrotheca is carried; apophysis frequently free from the axial tube but proximal region of the hydrotheca usually loosely adherent to the tube; hydrothecae regularly alternate: gonothecae closely aggregated, fused together

forming a coppinia with protective tubular structures standing out beyond the free surface of the gonothecae; gonothecal aperture where known, single, raised on a necklike structure which is hooded (Fig. 6, k) Cryptolaria Busk, 1857 Genus Hebella Allman, 1888 Hebellopsis Hadzi, 1913. Colony stolonal, hydrothecal pedicel arising directly from the stolons; hydrotheca cylindrical with entire margin, no operculum, usually with a diaphragm; gonothecae single, pedicellate arising from the stolon, distal aperture may be closed by an operculum of up to 6 valves; reproductive zooids producing free medusae. (In general, structures produced by the reproductive zooid and the structure of the gonothecae are not well known in the g. Hebella.) Of the three previously recorded species of Hebella from New Zealand, H. calcarata (L. Agassiz), H. cylindrica (von Lendenfeld) and H. corrugata (Thornely) only the cosmopolitan H. calcarata is represented in the present collection. This is unfortunate as H. cylindrica and H. corrugata (new recognised as H. costata corrugata) are known from only one locality in New Zealand and have not been taken since they were originally described by von Lendenfeld (1885) and Trebilcock (1928) respectively. Small collections of material from the Bay of Islands, the type locality of H. cylindrica, have been made over the last seven or eight years, but so far no material of H. cylindrica has come to hand. This may be because specimens were mainly taken from intertidal rock pools, and the hydroid hosts most favoured by species of Hebella in New Zealand—viz., Synthecium elegans and Sertularella sp., are sublittoral in habit. However, sufficient material of H. calcarata from both the North and South Islands has now been examined to give a good idea of the range of hydrothecal variation in New Zealand waters of this species and suggests that H. cylindrica may have been misidentified, and really a varietal form of H. calcarata. Sublittoral collections from several places in Cook Strait, the locality from which Trebilcock obtained his specimens of H. costata corrugata, have failed to reveal specimens of Hebella similar to the latter subspecies. H. calcarata is well known from this area, and although some specimens of this species are rather similar to H. costata corrugata they can be distinguished from the latter as they are smaller, and narrowly, not broadly cylindrical. Examination, however, of a small amount of Australian material from the Brisbane area suggests that H. costata corrugata as described by Trebilcock from New Zealand is H. costata costata. Key to the New Zealand Species of Hebella 1 (2) Hydrothecal length about twice as great as width; margin recurved, giving hydrotheca a trumpet-shape: gonotheca unknown. H. cylindrica (von Lendenfeld, 1885) 2 (1) Hydrothecal length about 3 times as great as width. 3 (4) Margin not usually everted or but slightly everted and horizontal; hydrothecal wall usually smooth or with slight waves; hydrotheca small, 0.75 mm or less in length (Fig. 1, a–n): gonotheca about twice the length of the hydrotheca, slightly compressed, distal end truncate and margin with 3 or 4 shallow emarginations; 3 or 4 opercular flaps closing aperture. H. calcarata (L. Agassiz, 1862) 4 (3) Margin clearly everted and oblique; hydrothecal wall annulated with up to 8 annulations; hydrotheca large, about 2.5 mm in length; pedicel long, up to 5.0 mm and undulated. H. costata (?) corrugata (Thornely, 1904)

Hebella calcarata (L. Agassiz, 1862). Fig. 1, a–s. 1862. Laodicea calcarata L. Agassiz, p. 350. 1865. Lafoea calcarata (L. Agassiz). A. Agassiz, p. 122, Figs. 184–194. 1888. Lafoëa scandens Bale, p. 758, Pl. XIII, Figs. 16–19. 1890. Hebella scandens (Bale). Marktanner-Turneretscher, p. 215, Pl. III, Fig. 16. 1890. Hebella cylindrica Marktanner-Turneretscher, p. 214, Pl. III, Fig. 15. 1896. Hebella scandens (Bale). Farquhar, p. 460. 1915. Hebella calcarata (L. Agassiz). Bale, p. 251 (synonymy). 1923. Hebella pusilla, Stechow, p. 5. 1924. Hebella calcarata (L. Agassiz). Bale, p. 235. 1928. Hebella calcarata (L. Agassiz). Trebilcock, p. 4. 1941. Hebellopsis scandens (Bale). Vervoort, p. 197. 1944. Hebella calcarata (L. Agassiz). Fraser, p. 205, Pl. 39, Fig. 183 (and for further synonymy). 1946. Hebella calcarata (L. Agassiz). Fraser, pp. 57 and 189. —— Hebella calcarata (L. Agassiz). Vervoort, p. 304. Colony stolonal; hydrorhiza rather delicate, about 0.13 mm in diameter, frequently twisted or with undulated perisarc, can be slightly reticulate and zooids given off irregularly but usually zooids given off regularly so that they frequently appear to be a part of the supporting hydroid host; exceptionally a portion may become erect without support; hydrotheca tubular, about three times as long as broad, but may be only twice as long as broad 0.62 mm to 0.75 mm in length and 0.21 mm to 0.25 mm in width; walls smooth or slightly undulated in the proximal region, more or less circular aperture, and entire slightly everted margin, horizontal or somewhat oblique plane of opening and distinctly thickened ring at base of hydrotheca; pedice short and smooth 0.093 to 0.125 mm in length and about 0.093 in width; pedicel and hydrotheca may be curved to one side; hydranth with dome-shaped hypostome and about 14 tentacles: gonotheca, about twice the length and width of the hydrotheca (1.0 to 1.25 mm in length and about 0.50 mm in width); slightly compresed, usually widest at the truncate distal end, narrowing to a short pedicel at the proximal end; walls smooth or with 3 to 5 distinct transverse undulations; distal margin with 3 or 4 shallow evaginations and 3 or 4 opercular flaps closing the distal aperture. Locality: Type locality, Buzzards Bay, North America: Auckland (Marktanner-Turneretscher, 1890); Stewart Island (Trebilcock, 1928); Tamaki Strait, Auckland, approx. 40 fath. (D. Kulka), 26/5/50, 545; Kawau Is., Hauraki Gulf, 5–13 fath. (M. Mackenzie), 18/7/56, 476; Cook Strait, V.U.Z. Stn. GUJ, 40–100 fath. (V.U. Zool. Dept.), 23/2/56. 522; Menzies Bay, Banks Peninsula (G. Knox), —/8/49, 240; off Karitane, Otago, 10 fath. (Hanson Bros. trawler “Grace”), 30/11/51, 265; E.S E. Otago Heads, “Alert” Stn. 54–4, 50 fath (E. J. Batham), 9/1/54, 543. Distribution: Cosmopolitan. Material of this species is abundant and ranges from Auckland, in the North Island, to Otago, in the South Island, so it seems likely that all varietal forms of the hydrotheca from our waters are now known. As yet, the species from New Zealand has only been observed epizoic on other hydroids, chiefly Synthecium elegans Allman, but this is probably because very little material of other suitable hosts such as species of Polyzans has been examined. The variation shown by the hydrotheca points to the possibility that H. cylindrica von Lendenfeld is misidentified, and a variety of the cosmopolitan H. calcarata. All the New Zealand material of H. calcarata shows the hydrotheca with a slightly everted margin and very short pedicel (0 062 to 0.12 mm in length) as described by Bale for his Australian specimens (= H. scandens cf. Bale 1915, p. 251 for synonymy). The hydrothecae, however, of the present material vary in the slope of the margin, the length to breadth ratio and in the wall structure particularly in the proximal region. Mostly, the margin is horizontal, but in a few it is distinctly oblique, and this latter condition is particularly apparent when the margin is duplicated or multiple (Fig. 1, d and h). The hydrotheca is usually three times as long as wide but may have a length only twice the width (Fig. 1, n and m), although this is rare. Some hydrothecae, particularly those on colonies from Cook Strait southwards, have undulated walls in the proximal region while other hydrothecae and their pedicels are curved to one side. Thus, the hydrothecae of H. calcarata in New Zealand show considerable variation, but this is not true of the gonotheca as at present

Text-fig. 1.—a–s, Hebella calcarata (L. Agassiz). a, habit on Synthecium elegans: b–e, hydrothecae from off Takapuna, Auckland; f and g, from Kawau Island, Hauraki Gulf; h–j, from Cook Strait; k–n, from off Karitane, Otago; o and p, distal view of gonotheca; q, gonotheca, r and s, hydranth and hydrotheca; t, * No size scale given.?Hebella cylindrica (von Lendenfeld) after von Lendenfeld Pl. XL, Fig. 5: u, Hebella costata (Bale), hydrotheca, from Cleveland, Queensland: v–x, * No size scale given. Hebella costata corrugata (Thornely). v, hydrotheca; w, pedicel of hydrotheca; x. gonotheca (v–x after Billard, 1941): y, Lafoea gracillima (Alder). Portion of polysiphonic stem.

known from localities as far apart as Auckland and Wellington. Gonothecae from these two localities are similar to those described and figured by Bale (1888) for the species. They all, however, have 4 emarginations each with an opercular flap, and there are none with 3 emarginations and 3 opercular flaps as observed by Bale. Gonothecae are present on Auckland area specimens of H. calcarata in May and July; Cook Strait specimens in February, and not present on my South Island material in August, November or February. Other material from Cook Strait, Menzies Bay, Christchurch, off Karitane and E.S.E. Otago Heads is without gonothecae, but the hydrothecae on these colonies show the same range of characters found on fertile colonies clearly H. calcarata that there is little doubt that this infertile material is also H. calcarata. Hebella cylindrica (von Lendenfeld, 1885) Fig. 1, t (after von Lendenfeld, Pl. XL, Fig. 5). 1885. Lafoea cylindrica von Lendenfeld, p. 912, Pl. XL, Figs. 4, 5. 1893. Hebella cylindrica (von Lendenfeld). Pictet, p. 41. 1896. Lafoëa cylindrica von Lendenfeld. Farquhar, p. 461. 1899. Hebella cylindrica (von Lendenfeld). Versluys, p. 31. 1903. Lafoëa cylindrica von Lendenfeld. Jaderholm, p. 274. 1930. Hebella cylindrica (von Lendenfeld). Totton, p. 155. 1944. Hebella (?) cylindrica (von Lendenfeld). Fraser, p. 206, Pl. 39, Fig. 184. 1946. Hebella (?) cylindrica (von Lendenfeld). Fraser, p. 190. —— Hebella cylindrica (von Lendenfeld). Vervoort, p. 305. (Discussion of specific status.) “The hydrorhiza is creeping, and closely adnate to the stem of other hydroids mainly Sertularians. It appears very small and slender and is not smooth. It runs in a straight line, keeps to the same side of the hydroid, and is attached throughout. From the creeping stem large hydrothecae (up to 1.0 mm Bale, 1913) arise, which are borne on very short and extremely narrow peduncles. The hydrotheca is mainly cylindrical and thin-walled; the margin is recurved so that it attains a trumpet shape. Near the bottom we find a perforated disc, forming a ring near the base of the hydrotheca; the hydranths are large and possess about 20 stout tentacles.” (von Lendenfeld): gonotheca—no reliable account of the gonotheca or reproductive zooid is known. (Cf. Vervoort, 1946, p. 305.) Locality: Type locality, Bay of Islands, New Zealand, and not known from this country since von Lendenfeld's original account. Distribution: New Zealand, Australia, Testigos Islands, St. Bartholomew Island, Off coast of Brazil, Aru Islands, Moluccas, and Amboina. From the recorded distribution of H. cylindrica it may be thought that this species is well known. Such is not the case, either for New Zealand, the type locality, or elsewhere. The species is known to me only from the literature and has not been taken in our waters since von Lendenfeld's original collection from the Bay of Islands. In general appearance H. cylindrica is similar to H. calcarata, and it is not improbable that H. cylindrica has been confused with this variable cosmopolitan species. Von Lendenfeld, however, describes the mouth of the hydrotheca as trumpet-shaped, with widely everted margin (Fig. 1, t) and the length about twice the width. Some hydrothecae on a colony of Hebella calcarata from off Karitane in the present collection have a length to breadth ratio similar to H. cylindrica, but the margin of the hydrothecae of these specimens of H. calcarata is not as widely everted (Fig. 1, m), as that figured by von Lendenfeld for the former species. More fertile material from North Auckland is necessary before a firm decision on the status of H. cylindrica can be given. Hebella costata Bale (?) corrugata (Thornely, 1904). (Text-fig. 1, v–x, after Billard, 1941 of H. costata corrugata.) 1884. Campanularia costaba Bale, p. 56, Pl. 1, Fig. 3. 1904 Campanularia corrugata Thornely, p. 114, Pl. 1, Fig. 2. 1910. Hebella corrugata (Thornely). Vanhöffen, p. 314. 1928. Hebella corrugata (Thornely). Trebilcock, p. 4. 1941 Hebella costata corrugata (Thornely). Billard, pp. 13–15, Figs. 3, 4 (for discussion of status and synonymy of “H. corrugata”.)

“Stems of varying length rise from a creeping stolon, both being thick and wrinkled but without rings. Hydrothecae about 1/10 of an inch in height usually, but varying in size with age; cylindric, the same width all their length; transversely ringed, more or less, sometimes with as many as 8 rings; the aperture obliquely sloped with an everted even rim which is often duplicated, while sometimes a complete new hydrotheca rises out of the old, its stem passing through this and standing at varying heights above it. Zooid with about 20 tentacles.” (Data from Thornely, 1904, for “Hebella corrugata”.) Locality: Type locality, Cheval Paar, Gulf of Manaar, 7–10 fathoms; Island Bay, Wellington (Trebilcock, 1928). Distribution:? Australia, Gulf of Manaar, Mergui Archipelago, Christmas Island, Japan, New Zealand, Zanzibar, Madagascar,? South Atlantic Ocean,? Natal. Trebilcock (1928) records Hebella corrugata (Thornely) from Island Bay, Cook Strait, New Zealand. Billard (1941) recognises H. corrugata as a subspecies of H. costata Bale, characterised by large hydrothecae up to 2.5 mm in length, long hydrothecal pedicel up to 5.0 mm in length, margin of the hydrotheca everted and sloped obliquely, undulated walls and gonotheca about 1.23. mm in length, pyriform with the distal end distinctly truncated and flat and a short, slightly undulated pedicel. The hydrothecae described by Trebilcock (1928, p. 4) from Cook Strait, seem similar in general appearance to those of H. costata corrugata, but much smaller (0.72 to 0.90 mm in length and 0.37 to 0.55 mm in width) and have the margin less oblique than that described for H. costata corrugata. Trebilcock's specimens were infertile. The size range of H. costata costata Bale, from Queensland (slide kindly loaned me by Miss Pamela Pennycuik) suggests that Trebilcock's material is H. costata costata, not H. costata corrugata. The average height of the Queensland material of H. costata costata is 1.0 mm and width 0.31 mm; the walls are clearly undulated and the margin slightly oblique. Both the Queensland specimens of H. costata costata and Trebilcock's from Cook Strait, whatever its systematic status, can be separated from other Cook Strait material here recognised as H. calcarata in which the hydrotheca has a similar length to breadth ratio, undulated walls and a slightly oblique margin. The greatest width of the hydrothecae in my specimens of H. calcarata is 0.25 mm, while in the Queensland specimens it is 0.40 mm, and in Trebilcock's 0.55 mm. Therefore, in general terms, the hydrothecae of H. calcarata from Cook Strait (and other New Zealand waters) are narrowly cylindrical, while those of H. costata (?) corrugata from the same locality are very broadly cylindrical. Furthermore, as known at present, H. costata (?) corrugata always has an oblique margin to the hydrotheca whereas this is an occasional feature in H. calcarata. Genus Lafoea Lamouroux, 1821 “Mature stems strongly fasciculed and erect, young stems may be creeping; hydrothecae with few exceptions, entirely free from the stem; no diaphragm in the hydrothecal cavity; no nematophores: gonangia in mass, usually forming a coppinia.” (Fraser.) The g. Lafoea is not well known from New Zealand. A small amount of material of L. gracillima (Alder) has been examined from Doubtful Sound (West Coast, South Island), the Chatham Islands and the Cook Strait area. Specimens from these localities show slight variation in the size and shape of the hydrotheca, but material is probably not adequate to show the full range of hydrothecal variation for this species from our waters. There is no material of L. dumosa in the present collection, the only other species of Lafoea recorded from New Zealand (Coughtrey, 1876). Coughtrey was doubtful of his identification (“several scraps of what I believe to be Lafoea dumosa”). As far as can be ascertained, his material is not now in existence, and the presence of L. dumosa in our waters is still in doubt. For quick reference, however, the species is separated from L. gracillima in the key below, but is not described or figured. L. dumosa is cosmopolitan and well known elsewhere.

Key to the New Zealand Species of Lafoea. 1 (2) Pedicel of hydrotheca short (about 0.19 to 0.22 mm in length) and slightly twisted. L. dumosa (Fleming, 1820). 1 (2) Pedicel of hydrotheca long (about 0.15 to 0.39 mm in length) and distinctly twisted. L. gracillima (Alder, 1856). Lafoea (?) dumosa (Fleming, 1820) 1820. Sertularia dumosa Fleming, p. 83. 1863. Lafoea dumosa (Fleming). M. Sars, p. 26. 1876. Lafoea dumosa (Fleming). Coughtrey, p. 299. 1896. Lafoea dumosa (?) (Fleming). Farquhar, p. 461. Locality: Type locality, Newhaven, among scraps from oyster beds; Wickliff Bay, Taiaroa Peninsula, Otago (Coughtrey, 1876). Lafoea gracillima (Alder, 1856). Figs. 1, y, and 2 a–c. 1856. Campanularia gracillima Alder, p. 361, Pl. XIV, Figs. 5–6. 1930. Lafoea gracillima (Alder). Totton, p. 158, Text-fig. 15. 1944. Lafoea gracillima (Alder). Fraser, p. 224, Pl. 46, Fig. 207. Mature erect stem polysiphonic up to 5.0 cm in height, irregularly branched; hydrotheca tubular, 0.43 to 0.68 mm in length exclusive of pedicel; pedicel long, 0.15 to 0.39 mm in length and usually with several distinct twists; margin of hydrotheca slightly everted, and often duplicated, diameter at margin 0.15 to 0.18 mm; gonothecae, aggregated into a coppinia, each gonotheca regularly hexagonal in shape when viewed from the free surface; aperture central on short neck; elongated hydrothecae emerge irregularly from among the gonothecae of the coppinia. (Coppinia very similar to that of L. dumosa but emergent hydrothecae more slender and in general longer, and gonothecae more regularly hexagonal (data on gonotheca after Fraser, 1944, p. 225). Locality: Type locality, Northumberland coast, Great Britain; Cook Strait (three localities), 40–100 fath., Stn. 55, 49 and 9 (V.U. Zoo. Dept.) 1954–55, 523, 525, and 535; Doubtful Sound, West Coast, 30 fath. on Aphanipathes aperta Totton (“New Golden Hind Expedition”) 18/2/46, 279; Chatham Rise, 280 fath. (Stn. 7, Chatham Exped. 1954), 24/1/54, Chatham Exped. Slide No. 7. Distribution: Essentially cosmopolitan. Specimens in the present collection have hydrothecae with characters described and figured by Totton (1930, p. 158, Text-fig. 15) for Lafoea gracillima (Alder). Hydrothecae on material from Doubtful Sound, West Coast, are very similar in size and shape to the holotype of the species, while those from off the Chatham Islands and Cook Strait are somewhat larger in size and similar to Totton's specimens from Cape Adare, Ross Sea. All the present specimens of L. gracillima are infertile. Genus Zygophylax Quelch, 1885 1888. Ltctorella Allman, p. 35 (cf. Totton, 1930, p. 164 for synonymy). Colonies usually sympodial, polysiphonic (rarely stolonal); branched, branches alternate to subaltenate, often pinnately arranged, generally simple, and monosiphonic; hydrothecae borne only by the axial tube and on an apophysis of that tube, never sessile, free, with distinct and sometimes long pedicel, and this usually marked off from the apophysis by a joint; a delicate diaphragm also present; nematothecae frequently present (but may be entirely wanting); when present may be on stem, branch or pedicel: gonothecae, aggregated, either joined together or quite separate, or intermediate, with some joined together and some separate; rather irregular in shape, with a varying number of tubular apertures, and these often provided with flared mouths; protective structures stretching beyond the gonothecae may be present, and these often tubular in shape. The two species of Zygophylax known from New Zealand, Z. sibogae Billard, 1918, and Z. unilateralis Totton, 1930, are rare, particularly Z. unilateralis which is described from a dozen stems, the tallest 6.0 cm., from off Three Kings Islands. This species is known to me only by a stem fragment of the type kindly loaned me by the British Museum (Nat. History). Z. sibogae described originally from the East Indies is also recorded from off Three Kings Islands (Totton, 1930). Totton's material was a simple young stem 15.0 mm in height. The two tall erect stems 7.8 and 9.0 cm in height in the present collection are from Mayor Island, Bay of Plenty area, and thus extend the known range of.

this species approximately 350 miles to the south. However, neither my tall specimens nor Totton's small stem of Z. sibogae show hydrothecae or nematothecae in any way different from those described by Billard for his material from the East Indies. The curving and flattening of the distal end of the hydrotheca “like a cobra's hood” is characteristic of Z. sibogae and it is easily distinguished by this feature from Z. unilateralis. Key to the New Zealand Species of Zygophylax 1 (2) Hydrothecae usually slightly shorter than the long pedicels which carry them; alternate in arrangement, sharply recurved and flattened like a cobra's hood. Z. sibogae Billard, 1918 2 (1) Hydrothecae about 3 times the length of the pedicels that carry them; more or less unilateral and curved aperture facing upwards and outwards so that those of one side at right angles to those of the other, giving a falsely bilateral appearance. Z. unilateralis Totton, 1930 Zygophylax sibogae Billard, 1918. Fig. 2, e–i. 1918. Zygophylax sibogae Billard, p. 21, Fig. 1. 1930. Zygophylax sibogae Billard, Totton, p. 167, Text-fig. 21. Colony pinnately branched up to 9.0 cm in height, main stem polysiphonic; axial tube of erect stem increasing in width from proximal to distal region up to 0.31 mm in diameter at proximal end and axial tube of branches up to 0.12 mm in diameter; accessory tubes bearing numerous narrow tubular nematothecae 0.05 to 0.12 mm in length (without regeneration), and 0.02 mm to 0.04 mm in diameter, 0.18 to 0.25 mm in length with regenerations; hydrothecae about 0.34 mm to 0.49 mm in length, and usually shorter than the long pedicels which carry then (0.34 to 0.50 mm in length); sharply recurved and flattened like a cobra's hood, constricted at bend, and wall of convex side in this region conspicuously thickened; mouth circular about 0.12 to 0.14 mm in diameter, without operculum, facing upwards and inwards towards the stem; diaphragm present; a short nematotheca usually present at the base of each pedicel on the inner side; pedicels not strictly lateral but having a tendency to be inclined to the inner side and separated from apophysis by a node; hydranth with about 12 tentacles and without lateral attachment: majority of gonothecae joined together, but some quite separate, irregular in shape with varying number of tubular openings provided with flared mouths. Locality: Type locality, Dutch East Indies; “Terra Nova” Stn 91, near Three Kings Islands, N. Z., 300 fathoms: Bay of Plenty, Stn 8, off Mayor Is, 80–120 fath (Northern Prawn Investigations, V.U Zoo. Dept.), 19/8/56, 503. Distribution: East Indies; New Zealand. Zygophylax unilateralis Totton, 1930. Fig. 2. d. 1930. Zygophylax unilateralis Totton, p. 167, Pl. I. Figs. 1, 2: Text-fig. 21. Colony polysiphonic; with well developed stem and branches up to 6.0 cm in height and with a main stem diameter of 1.0 mm; branches 0.10 mm in diameter; stem axial tube diameter 0.12 mm; hydrothecae more or less unilateral and curved aperture facing upwards and outwards so that those of one side are at right angles to those of the other, giving a falsely bilateral appearance; hydrothecae about 0.49 mm in length, approximately three times the length of the pedicel, which is about 0.17 mm in length; mouth aperture of hydrotheca about 0.20 mm; usually a node between every 3 hydrothecae; nematothecae present, one on the outer side of each stem or branch apophysis at the base of the hydrothecal pedicel: hydranth with an abcauline blind sac and about 10 tentacles: gonotheca, unknown. (Data after Totton, 1930.) Locality: Known only from the type locality, off Three Kings Is., New Zealand, from 300 fathoms. Genus Reticularia Wvville Thomson, 1853 1868. Filellum Hincks, p. 214 Colonies stolonal, frequently epizooic on other hydroids: proximal region of hydrotheca attached to stolon, free region curved upwards till almost at right angles to the attached region: no diaphragm: gonothecae aggregated into coppinia. Hincks' (1868) substitution of the g. Filellum for the g. Reticularia because the latter generic name was preoccupied for a plant has now no systematic status. Totton (1930, p. 161) revived the g. Reticularia Wyville Thomson, for species with the above characters.

Reticularia serrata (Clarke, 1879). Text-figs, 2, j, and 3, a. 1879. Lafoëa serrata Clarke, p. 242, Pl. IV, Fig. 25. 1905.? Filellum serpens (Hassell). Nutting, Pl. XIV, Fig. 7. 1928. Filellum serratum (Clarke). Trebilcock, p. 4. 1943. Filellum serratum (Clarke). Fraser, p. 90. 1944. Filellum serratum (Clarke). Fraser, p. 216, Pl. 44, Fig. 199 (synonymy). Colony stolonal, hydrorhiza about 0.062 mm in diameter with tubular hydrothecae arising from it at varying intervals; hydrotheca adnate to the hydrorhiza for a third to half its length in the proximal region; the free distal portion is bent at approximately a right angle to the adnate part and terminates in a slightly everted margin; total length of the hydrotheca from 0.40 mm to 0.50 mm; adnate portion 0.20 mm to 0.25 mm; maximum hydrothecal width about 0.14 mm; adnate region ornamented by a varying number (about 12) of external annular ridges: gonotheca unknown. Locality: Type locality, near Havana, Cuba, 292 fath.; Bluff; Stewart Island; Island Bay, Wellington (Trebilcock, 1928); Island Bay, Cook Strait (drift) (M. Aiken), 17/12/54, 451; Cook Strait cable (C. S. Recorder) —/—/32, 174. Distribution: West Indies, Mediterranean, Red Sea, East Indies, Indo-China, Philippines, Japan, New Zealand. Only R. serrata is known from New Zealand. The small amount of infertile material in the present collection is all from the Cook Strait area and has the hydrothecal characters described above. Double or multiple margins are surprisingly rare in this material and in some hydrothecae the proximal rings are very difficult to see. When this is the case, it is sometimes a problem to separate R. serrata from material of Lineolaria flexuosa, particularly if only young specimens of L. flexuosa are available, or those in which the hydrotheca is not attached to the substratum for the whole of its horizontal length. Nevertheless, the hydrothecae of R. serrata as at present known from New Zealand are only up to 0.50 mm in length, approximately ½ the total length of the hydrothecae of L. flexuosa. Furthermore, the strong attachment of the hydrothecae of L. flexuosa to the substratum makes it very difficult to remove them from the latter without damage, but the hydrothecae of R. serrata which are not so attached are freed with their stolons relatively easily. R. serrata was previously recorded from New Zealand by Trebilcock (1928) from three localities, one of which was Island Bay, Cook Strait. Trebilcock does not describe his material, so that no comparison can be made with present specimens from the same locality, but the latter are similar to those described by Fraser (1944, p. 216) from the Atlantic coast of North America. Genus Acryptolaria Norman, 1875 1857. Cryptolaria of authors not Busk, p. 173. 1875. Acryptolaria Norman, p. 172. —— Scapus Norman, p. 173. 1888. Non Perisiphonta Allman, p. 43. 1923. Oswaldaria Stechow, p. 147. 1930. Acryptolaria Norman. Totton, p. 169 (emended generic diagnosis). “Lafoeidae without a thecal diaphragm. Multipinnate. Branches of hydrocaulus alternate with every fourth theca on each side, in one plane, with irregular branches in other planes from accessory tubules. Hydrocaulus of stem and branches with a pair of main accessory tubes, one dorsal and the other ventral. On branches accessory tubes arise from level of proximal theca, and later give off from point of origin descending tubes, ventral ones descending stem, dorsal turning up stem. A foramen and coenenchymal connection formed at point of divergence. Mature specimens have stems composed of a great number of accessory tubes. These give rise to gonosome (Scapus, Norman, 1875) in form of closely packed flask-shaped gonothecae with short tubular mouths, surrounding stem for distances of two or three centimetres. No nematothecae, but smaller simple hydrothecae produced by accessory tubes”. (Totton, 1930.) Three species of Acryptolaria are known from New Zealand, A. gracilis (Allman, 1888), A. conferta (Allman, 1877) var. australis (Ritchie, 1911) and A. minima Totton, 1930.

Text-fig. 2.—a–c, Lafoea gracillima (Alder). d, Zygophylax unilateralis Totton. e–i, Zygophylax sibogae Billard. j, Reticularia serrata (Clarke).

A. conferta var. australis is the best known species of the genus from our waters. Totton (1930) previously recorded the species from off the Three Kings Islands, and it is represented in the present collection by two stems from the Chatham Islands and by 5 stems and three large pieces of stem from off Mayor Island, Bay of Plenty. Sufficient material of this varietal form has now been obtained to give a clear idea of the size and form of its hydrothecae so that it can be distinguished with confidence from A. gracilis (Allman) and A. minima, the other species of Acryptolaria at present known from our waters. A. minima was previously described from the far North of New Zealand at North Cape and off Cape Maria van Diemen (Totton, 1930). Present material is from Cook Strait approximately 500 miles further south. A. minima Totton seems to be a small variety of A. gracilis. This opinion is based on examination of material in the present collection of A. minima from Cook Strait, and two distal region fragments of erect stem labelled Cryptolaria gracilis Allman (now Acryptolaria gracilis (Allman)) which are part of a hydroid collection on loan to me from the Otago Museum. I suspect the latter are a portion of Allman's type material, but no information as to locality, etc., is given. The hydrothecae on these stem fragments are as described for A. gracilis. The similarity of shape of the hydrotheca, its plane of opening, etc., in A. minima (Fig. 3, e and f) and A. gracilis (Fig. 3, b–d) is so conspicuous that it is difficult to regard them as distinct, but the hydrotheca of A. minima is only about half the size of that of A. gracilis. It seems best for the present, therefore, to note the very close resemblance of these two species, but to recognise them as distinct, because our knowledge of A. minima is based on material from three localities only and that of A. gracilis from one. Key to the New Zealand Species of Acryptolaria 1 (4) Hydrothecae slightly curved outwards, and attached for approximately ⅔ their total length. 2 (3) Hydrothecae overlapping, long (about 1.0 mm in total length), abaxial wall of pedicel convex opposite the intersection of the distal wall of the pedicel and the erect stem; margin not everted, plane of opening about 60° to horizontal. A. gracilis (Allman, 1888) 3 (2) Hydrothecae overlapping, short (about 0.50 mm in total length); abaxial wall of pedicel distinctly convex opposite the intersection of the distal wall of the pedicel and the erect stem; margin not everted; plane of opening variable, 45° to about 55° to horizontal. A minima Totton, 1930 4 (1) Hydrotheca strongly curved outwards; hydrothecae adnate for about ½ their total length, narrowing towards the base; margin slightly everted; plane of opening variable but often more or less vertical; abaxial wall of hydrotheca evenly curved outwards; intersection of distal wall of pedicel and erect stem extending below the level of the emergence of the free portion of the preceding hydrotheca. A. conferta (Allman) var. australis (Ritchie, 1911). Acryptolaria gracilis (Allman, 1888). Fig. 3, b–d. 1888. Cryptolaria gracilis Allman, p. 42, Pl. XX, Fig. 2, 2a. 1896. Cryptolaria gracilis Allman, Farquhar, p. 461. 1930. Acryptolaria gracilis (Allman). Totton, p. 162. “Colony attaining a height of about two inches; stem slender, flaccid, much and irregularly branched and with the distal portion for a great extent destitute of peripheral tubes Hydrothecae alternate and distichous” (Allman); hydrothecae regularly alternate on axial tube of stem and branches adnate to the tube for approximately ⅔ their length (0.56 to 0.68 mm), free from the axial tube from 0.16 to 0.25 mm, margin smooth, not everted, infrequently duplicated or multiple, but up to 3 margins known; hydrothecae tubular, gradually bending outwards from the axial tube, abaxial wall with thickened perisarc; diameter at

aperture 0.14 to 0.18 mm; plane of opening about 60° the horizontal; distance between hydrothecae on the branches 1.14 to 1.25 mm; in monosiphonic regions of colony the abaxial wall of the pedicel is distinctly convex and sometimes slightly undulated: gonotheca, unknown. (Data from Allman's original description and a stem fragment from an unspecified locality in the hydroid collection of the Otago Museum, Dunedin.) Locality: Type locality, off East Cape, New Zealand, in 700 fathoms; not recorded from these waters since Allman's original description in 188. Acryptolaria minima Totton, 1930. Text-fig. 3, e and f. 1930. Acryptolaria minima Totton, p. 162, Text-fig. 18, a, b. Erect stems of colony up to 9.0 cm in height; polysiphonic, origin of branches and accessory tubes as described for the genus; hydrothecae overlapping, short, little curved; margin not everted, the plane in which it lies to the horizontal variable from 45° to about 55°; hydrothecae 0.61 to 0.73 mm apart, overall length about 0.52 mm, free portion about 0.07 to 0.11 mm in length: diameter at mouth of hydrothecae 0.13 to 0.15 mm; abaxial wall of pedicel distinctly convex, opposite the intersection of the distal wall of the pedicel and the axial tube; division between hydrotheca proper and pedicel marked by a row of bright “puncta”: gonothecae, closely packed and surrounding the stem, arising from accessory tubes, flask-shaped, with short tubular mouths; 0.61 to 0.73 mm in length; 0.12 mm in greatest width; mouth diameter 0.05 mm; tubular neck 0.12 mm in length (Data on gonothecae from Totton, 1930). Locality: Type locality, near North Cape, New Zealand, 11 to 20 fathoms “Terra Nova” Stn. 144 off Cape Maria van Diemen, 35 to 40 fathoms; Cook Strait, Stn. GUJ, 40–100 fath. (V.U. Zool. Dept.) 23/2/56, 524. Comparison of a portion of the type stem with my material shows the plane of opening of the hydrotheca in both about 55° to the horizontal. This seems to be a variable character, as Totton records 45° for the species. Acryptolaria conferta (Allman, 1877) var. australis (Ritchie, 1911). Fig. 4, a–g. 1911. Cryptolaria conferta var. australis Ritchie, p. 826, Pl. LXXXIV, Fig. 2; Pl. LXXXVII, Fig. 1. 1919. C. conferta var. australis Ritchie. Jaderholm, p. 7. 1930. Acryptolaria conferta var. australis (Ritchie). Totton, p. 163, Text-fig. 19, c, d. e. Erect stem of colony up to 5.0 cm in height, much and irregularly branched; on the free portion of the hydrothecal bearing axial tube the hydrothecae attached for about half their length (0.5 to 0.7 mm) and narrowing towards the base, the diameter of which is about 0.10 mm; abaxial wall of hydrotheca with an even curve outward; intersection of the distal wall of the pedicel and erect stem extending below the level of the emergence of the free portion of the preceding hydrotheca; aperture more or less circular, about 0.17 to 0.23 mm in diameter; margin slightly everted; hydranth elongate cylindrical, 7 to 9 short tentacles surrounding a dome-shaped hypostome: gonothecae aggregated, elongate flask-shaped, aperture on a distinct tubular neck; protective modified hydrothecae present. Locality: Type locality. “Thetis” Stn. 40, off Wata Mooli, 3 miles off-shore, 52 fathoms; “Terra Nova” Stn 91, off Three Kings Islands, 300 fathoms (Totton, 1930); off Mayor Is., Bay of Plenty, 50–100 fath. (Stn. 9. V.U. Zoo. Dept. Northern Prawn Investigation) 20/8/56, 508; E of Forty Fours. 130 fath (Stn. 34. Chathams Expedition, 1954), 1/2/54, Chat. Exped. Slide No. 8; Chatham Rise, 280 fath. (Stn. 7, Chat. Exped. 1954) 24/1/54, Chat. Exped. Slide No. 8a. Distribution: Australia, Japan, New Zealand. The present material is made up of 4 complete stems averaging 5.0 cm in height and 3 broken stems 3.0 cm from off Mayor Island, Bay of Plenty, and 2 broken stems 2.5 cm and 1.0 cm in height from the Chatham Island area. Two Bay of Plenty stems from an August collection are fertile, showing female coppinia. Chatham Island broken stems, collected in February, were infertile, but this amount of material is inadequate to say with certainty the state of fertility of colonies from this area during February. All the specimens from the Bay of Plenty show clearly the smooth outward curve of the hydrotheca; the intersection of the distal wall of the pedicel and erect stem extending below the level of the emergence of the free portion of the preceding hydrotheca, and a slightly everted margin. These features are characteristic of the var. australis. However, hydrothecae in specimens from the Chatham Islands especially towards the tips of the branches show the intersection of the distal wall of the pedicel ending about level with the emergence of the free portion of the

Text-fig. 3—a, Rebicularia serrata (Clarke) to show habit b–d, Acryptolaria gracilis (Allman); e–f, Acryptolaria minima Totton. e, from the type specimen; f, from specimen dredged 40–100 fath., Cook Strait: g, Acryptolaria conferta var. australis (Ritchie) to show habit.

preceding hydrotheca, a feature typical of A. conferta var. conferta. Further, a few hydrothecae in the distal monosiphonic region are slightly convex above the line of puncta (Fig. 4, b), that is, similar in shape to Clarke's figure of Allman's type of A. conferta var. conferta. Totton (1930, p. 164) observed a somewhat similar variation in specimens growing alongside each other from Madeira. Variation in Chatham Island material is not surprising, however, and is in line with previous findings (Ralph, 1956). It is well established that both Subtropical and Intermediate water are present seasonably in this area. As A. conferta becomes better known from the New Zealand area, variation will probably be shown to be related to material being taken from different latitudes, and subtropical, intermediate and subantarctic forms be demonstrated. In the meantime, Chatham Island material with some hydrothecae showing slight differences from those usually described as A. conferta var. australis are recognised as that varietal form. Genus Cryptolaria Busk, 1857 1877. Non Cryptolaria Allman, p. 17. 1888. Non Cryptolaria Allman, p. 37 and of authors (= Acryptolaria Norman, 1875). 1950. Non Cryptolaria Hodgson, p. 12. Branched polysiphonic colonies; hydrocaulus and branches with two distinct regions, an axial and a peripheral, the axial, a single tube bearing up to four longitudinal rows of hydrothecae, the peripheral surrounding the axial and without hydrothecae, usually a pair of accessory tubes one on each of the two opposite sides of the axial tube and numerous other accessory tubes, some of which arise as branches of the axial tube; the peripheral fascicle of the tubes may cover the axial tube to the tip of the stem and branches; hydrothecae narrowly tubular, in side view showing a distinct and often sharp outward curvature, convex on the adaxial side and concave on the abaxial, so that the aperture is approximately parallel to the long axis of stem and branches: carried on an apophysis of the axial tube sometimes termed a “pedicel”, the distal end of which is about the same diameter as the base of the hydrotheca but narrows towards the proximal end at its junction with the axial tube, the abaxial wall often bulging proximally so that hydrothecae and stem apophysis in side view show a double curvature—i.e., rather S-shaped; a distinct oblique joint (often termed a “diaphragm” separates the base of the hydrotheca from the stem apophysis: the opening of the stem apophysis into the axial tube round or oval and clearly visible in side view: hydrotheca closely adpressed, or loosely adherent to the axial tube for a portion of its length in the fascicled regions of colony, but may be free in non-fascicled regions; nematothecae present and found on all regions of the colony, on the peripheral tubes: gonothecae, aggregated, fused together forming a true coppinia, with modified tubular structures emerging and stretching beyond the gonothecae. usually branched at distal region and branches with nematothecae: aperture in known species single raised on a neck, and the aperture may be overhung by a distinct hood. The status of the g. Cryptolaria Busk. 1857 and its close relationship with the g Perisiphonia Allman. 1888, is discussed by Totton (1930, p. 166). Totton finds that Perisithonia auadriseriata Trebilcock, 1928, from Island Bay, Cook Strait, New Zealand is a synonymn of Cryptolaria prima. a species originally described from an unspecified “New Zealand” locality by Busk in 1857. Comparison of fertile material in the present collection recognisable as Perisiphonia pectinata Allman, 1888 (= genotype of Perisiphonia) and P. exserta Busk, 1858, with material of the g. Cryptolaria Busk, 1857, determines Perisiphonia as a synonym of the g Cryptolaria. (See Bale, 1915, p. 248 for discussion on the authority of Busk, 1858, instead of Johnson, for the species exserta.) Allman (1888) distinguished the genus Perisiphonia from Cryptolaria because the former possessed: hydrothecae with well defined peduncles instead of having the cavity directly continuous with that of the tube from which it arose; the axial tube not becoming free from the cover of the peripheral accessory tubes; and in the presence of a well developed system of nematothecae. It has now been adequately demonstrated by Totton (1930, pp. 161, 162 and 166) that Allman based his separation of these two genera on false premises as the characters he attributed to Cryptolaria were not those shown by the genotype of Cryptolaria Busk, 1857, but the characters of Acryptolaria Norman, 1875. From Totton's (1930) and Trebilcock's

(1928) observations, and from my own examination of New Zealand material in the present collection, the genotype of Cryptolaria is known to possess a distinct oblique joint (“diaphragm”) between the stem apophysis and the hydrotheca proper, thus separating the stem from the hydrotheca and forming what is generally termed a hydrothecal “pedicel” (Fig. 6, b); axial tube not free from the peripheral fascicle of accessory tubes; and a well developed system of nematothecae. These are the characters of the erect stem described by Allman for the g. Perisiphonia. There is, however, one erect stem character that distinguishes the genotype of Cryptolaria from that of Perisiphonia. A greater number of hydrothecal rows are borne by the axial tube of the branches in C. prima (Fig. 6, c) than in P. pectinata (Fig. 5, j). In C. prima four rows of alternating hydrothecae (in two series) are present on the branches and two rows on the main stem, while in P. pectinata there are two alternating rows on both the main stem and branches. Kramp (1943, p. 36), in discussing two Lafoeid genera closely allied to Cryptolaria and Perisiphonia, namely Acryptolaria and Grammaria, regards the varying arrangement of the hydrothecae on the main stem and branches as an unreliable character for separating these latter genera. As all other characters of the erect stem and hydrothecae in Perisiphonia and. Text-fig. 4.—a–g, Acryptolaria conferta var. australis (Ritchie). a–c, hydrothecae from Chatham Island material; d and e, hydrothecae from off Mayor Island, Bay of Plenty; f, surface view of portion of coppinia showing gonothecal apertures; g, lateral view of gonothecae dissected out from coppinia.

Cryptolaria have been shown to be identical, it seems likely that a different number of hydrothecal rows on the branches is not significant for separating these genera. Furthermore, the characters of the coppinia are similar in Cryptolaria and Perisiphonia, as in both the coppinia is formed of gonothecae that are joined together and have hooded apertures (Fig. 6, f, i, and k). From the above it is reasonable to conclude that the g. Perisiphonia Allman, 1888, is a synonym of the g. Cryptolaria Busk, 1857. In the past there has been difference of opinion on the systematic status of the five species of Cryptolaria—viz., C. prima, C. exserta, C. pectinata, C. filicula and C. chazaliei. C. prima, C. exserta and C. pectinata are now relatively well known and easily recognised. Of the other two species, C. filicula (Allman, 1888) and C. chazaliei (Versluys, 1899), the former is generally regarded as a synonym of C. exserta Busk, but the latter has at times been variously assigned either to C. exserta or C. pectinata and even to the g. Zygophylax (Fraser, 1944, p. 232). (Fraser has a different concept of Zygophylax Quelch, 1885, than is now in current usage following Totton's (1930, p. 164) findings; and it is reasonably certain that some North American material assigned by Fraser to the genera Zygophylax and Lictorella will be shown to be congeneric with Cryptolaria.) Kramp (1947) is convinced of the identity of C. chazaliei (Versluys) with C. pectinata, and is also of the opinion that “Zygophylax chazaliei (Clarke, 1907) is probably identical with P. exserta”. C. prima, C. exserta and C. pectinata are all known from New Zealand waters. C. exserta is a new record and here described from five pieces of stem averaging 1.0 cm in length. It is highly probable, however, that the pieces are all part of the one fertile stem. This material is clearly C. exserta as the hydrothecae are only slightly emergent beyond the peripheral fascicle of accessory tubules; possess a scarcely perceptible thickening of the abcauline wall where it bends outwards from the axial tube; usually a simple, not multiple hydrothecal margin, and nematothecae with fixed pedicel and movable cylindrical theca. C. pectinata as known to me from Ritchie's (1911) description of the type, some British Museum material, and from my own observations on a fertile specimen 5.2 cm in height in the present collection taken from about 150 miles N.W. of the type locality, has stem characters in sharp contrast to those of C. exserta. The hydrothecae extend well beyond the peripheral fascicle of accessory tubules, bend sharply away from the axial tube, have an internal thickening of perisarc on the abcauline wall where this wall bends outwards; a multiple margin with up to 13 successive margins known; and long nematothecae usually not divided into fixed pedicel and movable theca. New Zealand is the only country at present known in which all three species occur as C. prima has not as yet been taken other than in our waters. C. exserta and C. pectinata are better known from off tropical island groups—viz., C. exserta from Azores, Barbados, Testigos and Galapagos; and C. pectinata from Azores, Josephine Bank, Madeira, etc. C. exserta is also recorded from Australia and Tasmania. Apart from one or two very tall sertularian and plumularian species up to 3 to 4 feet in height, C. prima is the largest, most striking and easily recognised species of New Zealand thecate hydroids. Erect stems are thick, about 3.0 mm, and tall, up to 24.0 cm in height, stiff and straight. Branches are also stiff, pinnately arranged in subopposite pairs. Most of the rigidity of the stem and branches is obtained by the axial tube being surrounded by numerous accessory tubes that run to the tip of the stem and branches, none of the stem, etc., being monosiphonic. Similar pinnate branching is also characteristic of C. exserta and C. pectinata, but these species as at present known are only half the height of C. prima and the whole colony more slenderly built and delicate as the distal stem and branch tips have only one or two accessory tubes. Aggregations of gonothecae into a coppinia are conspicuous features of fertile colonies in all three species.

Unfortunately the hydranth of the species of Cryptolaria in the present material are too poorly preserved to give a description, and the species remain known by their skeletal structures only. Key to the New Zealand Species of Cryptolaria Busk, 1857 1 (4) Stem and branches with two longitudinal rows of hydrothecae; hydrothecae alternate. 2 (3) Hydrothecae rather cylindrical, and bending sharply away from the axial tube, adcauline wall with thickened chitin and distinct internal thickening of perisarc in abcauline wall where it bends abruptly outwards; regeneration of margin common up to 13 successive margins known; nematothecae cylindrical, usually not divided into fixed pedicel and free terminal portion: gonothecae fused, regularly arranged, more or less pentagonal in shape, aperture borne on a short neck and protected by a sharply pointed hood-like structure. C. pectinata (Allman, 1888) 3 (2) Hydrothecae extending but little beyond the peripheral fascicle, regeneration of margin uncommon; nematothecae usually with fixed pedicel and short, moveable cylindrical theca; gonothecae as for C. pectinata, but hood not so sharply pointed. Cryptolaria exserta Busk, 1858 4 (1) Hydrothecae arranged in a different number of alternating rows on stem and branches, usually two on the main stem and four on the branches: hydrothecae close set, usually overlapping proximal portion of successor in same series, cylindrical, terminal portion curving away from axis and projecting for short distance beyond peripheral fascicle of tubes; regeneration of the margin of hydrotheca not common but up to 4 successive margins known; nematothecae numerous, cylindrical with a short pedicel: coppinia large (up to 3.0 cm in length); gonothecae as for C. pectinata but hood low and dome-shaped Cryptolaria prima Busk, 1857 Cryptolaria pectinata (Allman, 1888). Fig. 5, g–j; 6, g–j. 1888. Perisiphonia pectinata Allman, p. 45, Pl. 21, Fig. 2. 1899. Perisiphonia chazaliei Versluys, p. 32, Figs. 2–4. 1900. Perisiphonia pectinata Allman. Pictet and Bedot, p. 18, Pl. 3, Figs. 1–4, Pl. 5. 1903. Zygophylax pectinata (Allman). Jaderholm, p. 278. 1907. Perisiphonia pectinata Allman. Browne, p. 28. 1911. Perisiphonia pectinata Allman. Ritchie, p. 835, Pl. 87, Fig. 2. 1925. Acryptolaria pectinata (Allman). Stechow, p. 448, Figs. 20, 21. 1930. Perisiphonia pectinata Allman. Totton, p. 166. 1947. Perisiphonia pectinata Allman. Kramp, p. 8. Erect stem branched, up to 12.0 cm in height, branches pmnately arranged sub-opposite; tubes of peripheral fascicle about 0.055 mm in diameter; hydrothecae regularly alternate on axial tube of stem and branches, adnate to axial tube for 0.36 to 0.38 mm, free from the peripheral fascicle of tubes from 0.31 to 0.32 including multiple margins which may be up to 13 in number, length of primary hydrotheca emergent from fascicle 0.15 to 0.19 mm; hydrotheca rather tubular and bending sharply away from the axial tube, so that the aperture is approximately parallel with the long axis of stem and branches, adcauline wall with thickened chitin and abcauline wall with distinct internal thickening of perisarc where it bends sharply outwards; hydrothecal diameter, at mouth 0.084 to 0.099; distance between hydrothecae on the branches 0.62 to 0.66 mm; hydrotheca borne on an apophysis of the axial tube (pedicel), about 0.12 mm in length with a bulge on the abcauline wall, approximately the same diameter as the hydrotheca distally, narrowed proximally at its junction with the axial tube, a distinct oblique joint (diaphragm) marks the apophysis from the hydrotheca; nematothecae arising from the peripheral tubes in all parts of the colony, generally cylindrical and not divided into fixed pedicel and free terminal portion as in C. exserta although a few of the type known from C. exserta may be present; total length of nematotheca, with marginal regenerations 0.15 to 0.28 mm, length of primary nematotheca 0.10 to 0.12 mm, diameter of nematothecae 0.024.

Text-fig. 5.—a–c, Cryptolaria prima Busk; a, portion of polysiphonic stem; b, nematotheca; c, end of branch to show peripheral fascicle of tubes, hydrothecae and nematothecae: d–f, Cryptolaria exserta Busk. d, portion of stem, e, nematotheca; f, end of branch of a cleared and mounted specimen; g–j, Cryptolaria pectinata (Allman). g, portion of stem; h and i, nematothecae; j, end of branch of a cleared and mounted specimen.

to 0.027 mm: gonothecae fused together forming a coppinia; each gonotheca polygonal in shape but with the distal end produced into a hood-like structure which is sharply pointed; aperture situated on one side of the hood-like structure; slender tubes arise between the gonothecae and project beyond the general surface of the coppinia; the distal free end of these tubes is usually irregularly branched and each branch carries a nematotheca. Locality: Type locality, off East Cape, N.Z., 700 fathoms; off Mayor Island, Stn. 9 “Northern Prawn Investigation” 50–110 fath. (V.U. Zoology Department), 20/8/56, 507. Distribution: Azores, Bay of Biscay Josephine Bank, east of Madeira, New Zealand. Features of the hydrothecae and nematothecae shown by a portion of stem of the type specimen of this species are similar to those shown by a single stem 5.2 cm in height from the Bay of Plenty. This is not surprising, as the type locality of C. pectinata is approximately 150 miles to the south-east—i.e., off East Cape. The present specimen seems to be female in sex. The single coppinia present is 1.3 cm in length and 2.0 mm in diameter and surrounds the proximal region of the main stem (Fig. 7, c), not a pinna. Cryptolaria exserta Busk, 1858. Fig. 5, d–f; 6, k. 1858. Cryptolaria exserta Busk, p. 130, Pl. XIX, Fig. 3. 1888. Perisiphonia filicula Allman, p. 44, Pl. XXII, Figs. 1–4. 1907.? Zygophylax chazaliei (Versluys). Clarke, p. 15, Pls. 11–13. 1911. Perisiphonia exserta (Johnson). Ritchie, p. 834, Pl. LXXXVII, Fig. 3. 1913. Perisiphonia exserta (Johnson). Stechow, p. 117. 1914. Perisiphonia exserta (Johnson). Briggs, p. 290. 1915. Perisiphonia exserta (Busk). Bale, p. 247. 1919.? Perisiphonia chazaliei Versluys. Nutting, p. 115. 1930. Perisiphonia exserta (Busk). Totton, p. 162. 1942. Cryptolaria exserta Busk. Blackburn, p. 111. 1944.? Zygophylax chazaliei (Versluys). Fraser, p. 232, Pl. 43, Fig. 196. 1946.? Zygophylax chazaliei (Versluys). Fraser, p. 187. 1947. Perisiphonia exserta (Johnson). Kramp, p. 8. Erect stems of colony attaining a height of about 7.0 cm, branched, branches pinnately disposed, equidistant, sub-opposite; tubes of the peripheral fascicle 0.045 to 0.07 mm in diameter; hydrothecae regularly alternate on axial tube of stem and branches adnate to axial tube for 0.25 to 0.36 mm, free from the peripheral fascicle of tubes 0.04 to 0.17 mm, margin infrequently regenerated; hydrotheca rather tubular, bending sharply away from the axial tube, so that the aperture is approximately parallel with the long axis of stem and branches, adcaulme wall with thickened chitin; hydrothecal diameter at mouth 0.09 to 0.14 mm; distance between hydrothecae on the branches 0.39 to 0.56 mm; hydrotheca borne on an apophysis of the axial tube usually termed a “pedicel” from 0.25 to 0.28 mm in length, approximately the same diameter as the hydrotheca distally, with a distinct bulge on the abcauline wall, narrowed proximally at its junction with the axial tube, a distinct oblique joint marks apophysis from the hydrotheca, and this generally termed a “diaphragm”; nematothecae arising from the peripheral tubes on all parts of the colony, usually divided into a fixed pedicel and free terminal cup-shaped portion, and this latter usually with an oblique “diaphragm-like” structure, length of pedicel 0.02 to 0.06 mm, total length 0.055 to 0.12 mm, breadth at aperture 0.027 to 0.030 mm: female coppinia surrounding the branch and sometimes the main stem for up to 2.0 cm and about 2.0 mm in diameter; gonothecae fused to one another on all sides, regularly arranged, arising from tubes of the peripheral fascicle, more or less pentagonal in shape, widest at the distal end, tapering towards the base; aperture carried on a small conical neck; aperture about 0.06 m in diameter, protected by a large hood-like structure; tubes of the peripheral fascicle standing out more or less at right angles beyond the gonothecae for up to 0.70 mm (giving the whole structure a “prickly” appearance), tubes branched at the distal region, and branches bearing nematothecae very similar to those described for the main stem and branches. Locality: Type locality, Madeira; Cook Strait from the submarine cable, collected by the “C.S. Recorder”, 1932, 173. Distribution: Madeira, Tasmania, Australia (several localities), Azores, Japan, off Barbados; off Testigos Island, Galapagos Island, New Zealand. Cryptolaria prima Busk, 1857. Figs. 5, a–c; 6, a–f; 7, a and b. 1857. Cryptolaria prima Busk, p. 173. 1928. Perisiphonia quadriseriata Trebilcock, p. 4, Pl. II, Fig. 2. 1930. Cryptolaria prima Busk, Totton, p. 161 and 166. Attachment of colony by a tangled mass of tubes more or less aggregated to form a disc-shaped structure up to 2.5 cm in diameter; erect stem tall, up to 24.0 cm in height, stiff,

Text-fig. 6.—a–f, Cryptolaria prima Busk, a, hydrotheca to show multiple margin; b and c, hydrothecae of axial tube and branches dissected out from peripheral fascicle of accessory tubes; d, surface view of peripheral fascicle of accessory tubes in region of incipient coppinia (after brief boiling in caustic potash); e, surface view of coppinia to show hooded apertures of gonothecae; f, lateral view of gonothecae dissected out from coppinia; g–j, Cryptolaria pectinata (Allman): g and h, hydrotheca with multiple margins, type specimen; i–j, lateral surface and view of a few gonothecae: k, Cryptolaria exserta Busk. Lateral view of a few gonothecae from coppinia. Abbreviations: a, aperture of gonotheca; ah, aperture of hydrotheca; ept, erect peripheral tube; g, interior of gonotheca; h, hood of gonotheca; n, nematotheca; ne, neck; pft, peripheral fascicle of tubes.

branched and branches regularly and pinnately arranged, pinnae subopposite forming an angle of 60° with the main stem and up to about 5.0 cm in length; rather oval in cross section; main stem and branches with single axial tube giving rise to hydrothecae and surrounded by a fascicle of peripheral tubes bearing only nematothecae; hydrothecae on main stem in two alternating series on opposite sides of the axial tube but in the same plane; on the branches in four series, two alternating close together on the abcauline, and two close together on the adcauline side, but abcauline and adcauline hydrothecal rows widely separated; individual hydrothecae usually overlapping the proximal region of its successor in the same series, cylindrical, but distal region curving away from the axial tube and projecting through the fascicle of peripheral tubes for 0.125 to 0.15 mm; aperture circular, smooth and 0.125 to 0.156 mm in diameter; margin may be regenerated, up to 4 regenerations known; base of hydrotheca passing into well defined apophysis of the axial tube (pedicel), about 0.25 mm in length; distinct oblique “diaphragm” between pedicel and hydrotheca proper; length from aperture to diaphragm 0.48 to 0.52 mm, and 0.125 to 0.156 mm in width; nematothecae numerous, on hydrorhiza, stem and branches, rather cylindrical, usually with thin diaphragm-like partition borne on projection (pedicel) from a peripheral tube, and separated from projection by a constriction; 0.10 to 0.13 mm in total length (i.e., inclusive of pedicel) and 0.025 to 0.037 mm in greatest diameter; peripheral tubes communicate with each other and the axial tube of main stem by an oval or circular aperture, but communicate with the axial tube of the branch only at the extreme proximal end and within the peripheral tubes of the main stem; main stem with thick-walled axial tube; axial tube of branch thin-walled and arising from the base of a thick-walled hydrotheca: coppinia large, surrounding the branch for up to 3.0 cm and about 2.0 mm in diameter; gonothecae fused to one another on all sides, regularly arranged arising from tubes of the peripheral fascicle, more or less pentagonal in shape, widest at the distal end, tapering towards the base; aperture carried on a small conical neck; aperture about 0.06 mm in diameter, protected by a dome-shaped hood-like structure; tubes of the peripheral fascicle emergent beyond the gonothecae for up to 1.2 mm (giving the whole structure a prickly appearance), tubes branched at the distal region, and branches bearing nematothecae similar to those described for the main stem and branches. Locality: Type locality, New Zealand (Busk, 1857); Island Bay (Trebilcock, 1928); Pelorcus Sound, drift (J. Hay),—/7/50, 128; White Rock, Cook Strait, nest King Shag colony (K. A. Wodzicki), 25/7/50, 196; off Kapiti Island, west coast N.I., 20–40 fath. (Trawler “Thomas Currell”) 5/9/55, 618; off Timaru, 40 fath. (P.M.R.) 25/11/51, 257; off Moeraki, east coast S.I., 40 fath. (P.M.R.) 12/2/51, 72; off Otago, 80–100 fath. “Alert” Stn. 55–4 (E. J. Batham), 14/8/55, 541. Abundant material of this species was obtained off Moeraki, east coast South Island, in about 40 fathoms during a trip with the large commercial fishing trawler “Taiaroa”. The area off Moeraki is known to the fishermen as “the weed bed”, and from what was observed it is well named, as the nets came up bulging with seaweed and large quantities of hydroid material. C. prima was the dominant hydroid present. Tallest colonies were 24.0 cm in height and there were few stems less than 20.0 cm. The basal attachment disc of many colonies was 1.0 cm in diameter. As coppinia are a prominent feature on fertile erect stems, an estimate was made of the number of planulae that might be liberated by an erect stem on which there are 20 coppiniae (on 11 consecutive pairs of branches). Their average length is 3.0 cm and diameter 2.0 mm. In general there are 64 gonothecae to a square millimeter, 9.0 sq. mm in a coppinia and therefore 576 gonothecae per coppinia. It is difficult to give an exact figure for the number of planulae per gonotheca, but from observations on the average number of mature eggs left in the gonothecae, a count of four would be a very conservative estimate. This gives a total of 2,304 planulae per coppinia and for the stem with 20 coppinia a total of 46,080 planulae. Such numbers could account for the dense beds of this hydroid in apparently localised areas. The large amount of material obtained from off Kaikoura (east coast S.I.), through Cook Strait and northward to Kapiti Island (west coast N.I.) indicates extensive beds in these areas as well as off the east coast of the South Island round Moeraki. A King Shag nest from White Rock, Cook Strait, was built largely of the stems of C. prima. Ripe coppinia are present on colonies taken in July, August, September, November and February.

Text-fig. 7.—a and b, Cryptolaria prima Busk. Large fertile erect stems to show habit: c, Cryptolaria pectinata (Allman). Small fertile erect stem to show habit. Family Lineolariidae Allman, 1864 Colony creeping with no erect stem, hydrotheca and gonotheca with very short or rudimentary stalk; stalk attached to the hydrorhiza and substratum, as is the proximal region of the hydrotheca; distal region of hydrotheca free, sometimes almost at right angles to the attached region; gonotheca single, and also attached to the substratum by one surface; structures produced by the reproductive zooid unknown. A small family containing only the genus Lineolaria Hincks, 1861, and as known, confined to Australian and New Zealand waters. Only L. flexuosa Bale, 1884, is recorded from Stewart Island, New Zealand, by Trebilcock (1928). The other two species, L. spinulosa Hincks (genotype) and L. inarmata Blackburn, 1938, are found in Victorian waters, Australia. The creeping habit of Lineolaria give the colonies a general aspect similar to species of g. Reticularia in F. Lafoeidae, but the single gonotheca and the attachment of this structure and the hydrotheca to the substratum distinguish the species and place them in separate families. In the present collection L. flexuosa is known from one North Island and two South Island localities. My specimens are infertile and I am indebted to Dr. Maurice Blackburn for allowing me to see microslides of his material from Sir Joseph Banks Islands, from which the sketches of the gonothecae (Fig. 8, g and h) and some hydrothecae (Fig. 8, d–f) were made. Genus Lineolaria Hincks, 1861 Generic characters as for the family. Lineolaria flexuosa Bale, 1884.- Fig. 8, a–h. 1884. Lineolaria flexuosa Bale, p. 62, Pl. I, Figs. 7–9. 1887. Lineolaria flexuosa Bale, p. 91. 1928. Lineolaria flexuosa Trebilcock, p. 8. 1938. Lineolaria flexuosa Blackburn, p. 321. Hydrorhiza flexuous or straight, about 0.125 mm in diameter, giving origin to single hydrothecae that lie almost parallel or at right angles to the hydrorhiza; hydrothecae alternate, the proximal region rather oblong in shape and the abcauline wall may be undulated; distal region free, more or less at right angles to the proximal, variable in length (0.37 to 0.70 mm) and may be equal in length to the adnate region, occasionally with a lateral wing or expansion: gonothecae variable in shape, elongate or broadly eliptic, often convex above with irregular transverse ridges; terminal aperture large, about 0.21 mm in diameter, margin elevated and flaring, operculate; a number of long, erect spines about 20 in number on the upper side of the gonotheca; overall length 0.56 to 0.75 mm and about 0.37 to 0.56 mm in greatest diameter. Locality: Type locality, Williamstown (Victoria), Australia; off Cape Maria van Diemen, 10 miles N.W., 50 fath., on Synthecium elegans forma subventricosum Bale (G. Knox),

—/—/—, 419; Pelorous Sound, 25–30 fath. (W. H. Dawbin), 26/12/51, 534; Otago Canyon A, 250 fath. (E. J. Batham), 14/8/55, 540; Stewart Island (Trebilcock, 1928). Distribution: Australia, New Zealand. Family Haleciidae Hincks, 1868 Colonies of variable habit either stolonal or sympodial, monosiphonic or polysiphonic; hydrotheca reduced to a saucer-shaped “hydrophore too small to lodge the contracted hydranths, and usually carried on a tubular pedicel; margin entire, often flaring; regeneration from primary hydrotheca common, giving a series of secondary, tertiary, etc., hydrothecae; a circle of bright dots (puncta) just below the rim of the hydrotheca; hydranth with conical proboscis; nematothecae may be present: male and female gonothecae usually of different size and shape; reproductive zooids producing fixed sporosacs or medusoid structures. Examination of material in the present collection taken mainly over the last five years has increased our knowledge of this family in New Zealand waters by 60%. This suggests that other species will be found in our waters. The cosmopolitan H. beanii and H. sessile are recorded for the first time in this paper and also probably H. tenellum, although material of this species is inadequate to give a firm decision on its specific identity. Other new records for New Zealand are the rare H. fragile Hodgson, known elsewhere only from Tasmania, and the relatively rare Hydrodendron caciniformis Ritchie from Cape Verde Is., West Indies, Mediterranean and South Africa. Unfortunately there is no specimen of the unique Hemitheca intermedia Hilgendorf in the present collection, although variously hydroid species have been taken in recent years from the wharf piles in Otago Harbour, the type locality of the species. The status, therefore, of H. intermedia remains rather puzzling. Present material, however, determines the status of Halecium delicatulum Coughtrey, 1876. This New Zealand species has largely been overlooked in the past because previous descriptions have been based on inadequate material. The evidence of all the material now available indicates that Halecium gracile Bale, 1888, Halecium parvulum Bale, 1888, and Halecium flexile Allman, 1888, are synonyms of H. delicatulum. Specimens of H. delicatulum have been taken from both main Islands and from the intertidal region and down to 300 fathoms. It is now the best known species of Halecium from New Zealand. Halecium corrugatissimum, Halecium lenticulare and Hydrodendron armata are known only from New Zealand and described from a few localities, so the full range of variation is unlikely to be shown by the present material. It also seems possible that H. corrugatissimum Trebilcock, 1928, is misidentified and a varietal form of Halecium speciosum Nutting, 1901. Key to the New Zealand of F. Haleciidae 1 (4) Erect stem without nematothecae. 2 (3) Hydrothecae confined to the branches and borne on a process of the internode; a small ridge present between stem process and hydrotheca; no regeneration of primary hydrotheca giving a series of secondary, tertiary hydrothecae, etc. Hemitheca Hilgendorf, 1898 3 (2) Hydrothecae not confined to the branches, and these may or may not be borne on a process of the internode; regeneration of hydrothecae common, giving a series of secondary, tertiary, etc. Halecium Oken, 1815 4 (1) Nematothecae on stem and/or branches; hydrothecae similar to those of Halecium. Hydrodendron Hincks, 1874 Genus Hemitheca Hilgendorf, 1898 Colony monosiphonic, branched, stem and branches divided into internodes by “distinct constrictions in a conspicuous perisarc”, branches regularly alternating from the distal part of each stem, internode and branches may themselves be irregularly branched; hydrothecae confined to the branches and borne on an internodal process of the branch, a small intrathecal

ridge is present, only primary hydrothecae present; hydranth with a conical hypostome, surrounded by 18 tentacles disposed in a single row; gonotheca and reproductive zooid unknown. The genus Hemitheca Hilgendorf, 1898 (monospecific H. intermedia) was originally assigned by Hilgendorf to the athecate F. Bougainvillidae because the hydranth has a single whorl of tentacles surrounding a conical hypostome and the zooids cannot be completely retracted within the hydrotheca. Stechow (1913) was the first to recognise Hemitheca intermedia as a species of thecate hydroid of the family Haleciidae. He comes to this conclusion because in his opinion the joints on the stem are characteristic of thecates rather than athecates, the hydranths of H. intermedia are identical with those known for members of the F. Haleciidae, and the hydrotheca although not typical is most nearly related in form to those described for the latter family. Stechow's recognition of H. intermedia as a thecate species of F. Haleciidae seems a logical conclusion from the available evidence and the species is regarded here as a member of that family. Bale (1924) gives no reason for his retention of H. intermedia in the F. Bougainvillidae and Findlay (1928) points out that Bale is in error in perpetuating Hilgendorf's original misinterpretation. Text-fig. 8—a–h, Lineolaria flexuosa Bale, a–c, hydrothecae from New Zealand material; d–f, hydrothecae from Reevesby Island, Australia; g and h, gonothecae from Reevesby Island material,

No type specimen is known to exist, and concept of the species must be based on Hilgendor's description and figures. He clearly considers that there are no hydrothecae on the main stem, and this character marks g. Hemitheca as unique in the F. Haleciidae. Hemitheca intermedia Hilgendorf, 1898, Fig. 8, a and b (after Hilgendorf, 1898, Pl. XVI, Fig. 2, 2a). 1898. Hemitheca intermedia Hilgendorf, p. 202, Pl. XVI, Figs. 2, 2a. 1913. Hemitheca intermedia Hilgendorf. Stechow, p. 23, Fig. 3. 1924. Hemitheca intermedia Hilgendorf. Bale, p. 228. 1928. Hemitheca intermedia Hilgendorf. Finlay, p. 257. Locality: Type locality, Dunedin, New Zealand, on submerged wharf piles (The species has not been taken since Hilgendorf's original collection.) Genus Halecium Oken, 1815 Colonies stolonal or sympodial; monosiphonic or polysiphonic and both habits known for some species; hydrotheca reduced to a saucer-shaped “hydrophore” too small to lodge the contracted hydranths, usually carried on a tubular pedicel; margin entire, often flaring; regeneration from primary hydrotheca giving secondary, tertiary, etc., hydrothecae common; hydrothecae usually with a circle of bright dots (puncta) just below the margin; hydranth with conical proboscis; no nematothecae present: male and female gonothecae often of different size and shape; reproductive zooids producing fixed sporosacs. This is the best known and most widely distributed genus of the family, and in New Zealand its species represent 75% of the halecid fauna. Key to the Species of Halecium in New Zealand 1 (2) Erect stem and branches strongly annulated: branching falsely dichotomous or trichotomous; female gonotheca ovoid, distinctly and evenly annulated, but distal end smooth and rather truncate; aperture on a short tubular projection about half way up the side; male gonotheca unknown. H. corrugatissimum Trebilcock, 1928 2 (1) Erect stem not strongly annulated. 3 (14) Margin of hydrotheca flared. 4 (7) Margin of hydrotheca flared on one side only. 5 (6) Margin flared, particularly on the adcauline side; and hydrotheca with well developed thickening below the diaphragm; erect stem usually regularly and markedly sympodial; male gonotheca on distal stem region, small ovate and much flattened; female on proximal region, large, lenticular, with circular aperture on distal abcauline side. H. lenticulare Trebilcock, 1928 6 (5) Margin slightly flared on the abcauline side; hydrothecae with extremely short pedicels practically sessile on the small shelf-like process on the distal region of the internode; puncta prominent; male gonotheca almost cylindrical rounded at distal end; female, rather kidney-shaped, two small hydranths emerging through a raised aperture in the region of the concavity. H. sessile Norman, 1866 7 (4) Margin with even flare all round. 8 (9) Margin with very slight flare: stem internodes short and thick, nodes well marked, straight or slightly oblique: male gonotheca oblong-oval; female elongate but curving to one side distally with lateral aperture on thumb-like process through which two small hydranths emerge. H. beanii (Johnston, 1838)

9 (8) Margin with broad distinct flare. 10 (11) Nodes twisted, oblique, sloping alternately in opposite directions; erect stem either large and polysiphonic (up to 10.0 cm) with main stem and branches distinctly fascicled, and only the distal region of stem monosiphonic; or small, stems (up to 3.0 cm in height) and monosiphonic: male gonotheca compressed when fully grown; ovoid in broader view, pyriform or club-shaped when immature; female gonotheca large, ovate, compressed, and when fully grown with two distinct peaks on either side of the terminal aperture. H. delicatulum Coughtrey, 1876 11 (10) Nodes straight or slightly oblique; erect stem small, narrow and delicate, up to 5.0 mm in height. 12 (13) Nodes straight, stem internodes all about the same length, smooth, cylindrical or sometimes with irregular constrictions; branches alternate, arising from a small lateral process below the primary hydrotheca. H. fragile Hodgson, 1950 13 (12) Nodes straight to slightly oblique; stem internodes very irregular in length, often devoid of hydrophores, annulated above and below the nodes; branches often arising in pairs; secondary hydrophores annulated at base. Halecium tenellum Hincks, 1861 14 (3) Margin of hydrotheca not flared: erect stem small, about 6.0 mm monosiphonic, exceptionally with main stem strengthened by 1 or 2 irregular peripheral tubes; distal branching usually active, giving “bushy” appearance; primary hydrotheca sessile, secondary with large basal cavity; walls thick: gonotheca unknown. H. expansum Trebilcock, 1928 Halecium corrugatissimum Trebilcock, 1928. Fig. 9, c-f. 1928. Halecium corrugatissimum Trebilcock, p. 7, Pl III, Fig. 1. Erect stems up to 5.0 cm in height; monosiphonic strongly annulated; growth form irregularly sympodial, and main axis not produced beyond the primary hydrotheca and one, two or three branches arise from immediately below the diaphragm of the primary hydrotheca so that the branching is falsely dichotomous or trichotomous; branching not in one plane; hydrothecal pedicels expanding distally, 0.50 mm to 062 mm in length, deeply corrugated; hydrotheca, 0 125 to 0.187 mm wide and 0.031 to 0.040 mm deep as measured from puncta to margin; margin expanding and slightly flared, margin or hydrotheca sometimes regenerated; diaphragm fairly well developed, but thin, wide aperture about 0.062 mm: hydranth with about 15 tentacles; female gonothecae arising below the hydrotheca, mainly on the distal region of the stem, ovoid with from 5 to 7 distinct annulations: summit usually devoid of annulations, and more or less rounded, aperture lateral on a short neck about half way up the side; male gonotheca unknown. Locality: Type locality, St. Clair, Dunedin. Off Glendowie. Auckland (drift),-(C. Trevathen),—/10/49, 553: Devonport. Auckland (R Kulka), 26/5/50, 554; Goat Island, Otago Harbour (B. Brewin), 2/12/44, 447; Portobello Marine Biological Station reef (P.M.R.),—/12/52, 448. (Known only from New Zealand.) The above description is based on material in the present collection from Auckland and Otago Harbour and that of Trebilcock (1928). My specimens from Auckland have mature female gonothecae. These suggest that the gonothecae on Trebilcock's specimen were immature, as the present female gonothecae clearly show the gonothecal aperture carried on a small tubular neck about half-way up one side, a feature not described by Trebilcock. Two small hydranths emerge through the aperture. The characters of the stem and hydrothecae are otherwise similar to those known for H. corrugatissimum. Trebilcock (1928) recognised H. corrugatissimum as very closely allied to H. speciosum Nutting 1901, but did not say how they were to be separated. H. corrugatissimum as known from New Zealand possesses very short internodes while.

Text-fig. 9.—a and b, Hemitheca intermedia Hilgendorf After Hilgendorf, 1898, Pl. XVI, Figs. 2, 2a: c–f, Halecium corrugatissimum Trebilcock; (e, young gonotheca after Trebilcock 1928, Pl. III, Fig. 1): g, Halecium lenticulare Trebilcock. Portion of erect stem, h and 1, Halecium sessile Norman.

H. speciosum has the “origin of the pedicels taking the place of nodes”. The apparent difference in the stem and branch characters of the two species could be due to a difference in descriptive terminology rather than a real difference in structure, and certainly the New Zealand material of H. corrugatissimum could be described in Nutting's words (see Trebilcock, 1928, Figs. 1 and 1a; and Fig. 9, c of the present paper). The extensive annulation of the stem and branches makes it difficult to determine which are the joints separating internodes and which separating those of the hydrothecal pedicel. The ultimate branching form assumed by H. corrugatissimum, however, appears distinct from that of H. speciosum. Trebilcock (1928) describes falsely dichotomous or trichotomous branching as a feature of the erect stem of H. corrugatissimum because the main axis does not extend beyond the primary hydrothecae, and this is true of all the known New Zealand material. In H. speciosum, branching is more irregular, and although there may be regular alternation, this is not in one plane. The hydrothecae of both species are very similar, and the gonothecae are figured as ovoid and annulated, with the distal end rather truncated but also rounded and without annulation. H. speciosum has a long annulated pedicel whereas H. corrugatissimum has a non annulated and shorter pedicel about 0.093 mm. Fraser (1937), quoting Nutting, does not describe the gonothecal aperture of H. speciosum, and it seems likely that his North American material is immature, similar to Trebilcock's specimens from New Zealand. Nevertheless, despite obvious similarities, it seems best for the present because of the diffrent mode of branching and the longer gonothecal pedicel to keep the species separate. Halecium lenticulare Trebilcock, 1928. Fig. 9, g. 1928 Halecium lenticulare Trebilcock, p. 6, Pl. III, Fig. 3. Erect stem small, about 1.0 cm in height, monosiphonic, usually regularly and markedly sympodial in growth habit, and with definite zig-zag appearance, but may be straight; thickness of perisarc on stem and branches may be thick and strengthened by internal annulations; primary hydrothecae low, secondary with large basal cavity, somewhat symmetrically developed, hydrothecae usually with very thin walls, margin slightly flared, on the adcauline side; diaphragm well developed but extremely thin, aperture narrow, often terminating in a very delicate membranous tube which stretches a considerable distance into the basal cavity; below the diaphragm a well developed thickening of the wall often extending completely round the hydrophore but always thicker on the adcauline side, sometimes another similar thickening, but not so pronounced, nearer the bottom of the basal cavity; regenerations of the hydrotheca common: gonothecae borne on an apophysis immediately below the primary hydrotheca; male gonothecae borne mainly on the distal parts of the stem, small ovate, and much flattened; female gonothecae usually confined to the proximal parts of the stem; large, lenticular, with a circular opening in the distal part of the abcauline side, margin of opening thickened. Locality: Type locality, Bluff Harbour. St. Clair, Dunedin; Island Bay, Wellington (Trebilcock, 1928); Palliser Bay, Cook Strait on crayfish appendages (R. W. Zander), 6/9/56, 497. Another rare species known only from New Zealand waters. The present collection of 23 complete stems from Palliser Bay, Cook Strait, about 20 miles south-east from where Trebilcock (1928) took some of his original specimens, adds nothing new to the description already given by Trebilcock for material from the Cook Strait area. It is interesting to note, however, from present material, that the species may be epizoic on crayfish appendages. The flat lenticular female gonothecae are distinctive and very conspicuous features of a fertile stem. No male gonothecae and only empty female gonothecae are found on my material taken in September. Halecium sessile Norman, 1866. Figs. 9, h and i; 10, c and d. 1866. Halecium sessile Norman, p. 196. 1904. Halecium sessile Norman. Billard, pp. 157–160, Pl. VI, Figs. 1–14. 1911. Halecium sessile Norman. Ritchie, p. 812, Pl. LXXXVII, Figs. 8–9. 1944. Halecium sessile Norman. Fraser, p. 201, Pl. 37, fig. 178. Erect stem up to 10.0 mm in height, monosiphonic; irregularly branched, and branches like main stem in character; branches may be in different planes; main stem internodes 0.50 mm to 0.68 mm in length, branch internodes 0.16 to 0.31 mm and 0.125 mm in width; node, distinct, rather oblique, sloping alternately in opposite directions; hydrothecae alternate, funnel-shaped, about 0.125 mm wide and 0.015 to 0.020 mm deep, margin to line of puncta; almost.

completely sessile; pedicels arise from small “process” at the distal end of the internode; margin may be very slightly everted; puncta prominent; hydranths large, about 0.62 mm when fully extended, and gradually expanding from the proximal to the distal region, but a sharp increase in width in the region of the hypostome, tentacles about 20 in number: male gonotheca rather cylindrical 0.62 mm to 0.75 mm in length and about 0.21 mm wide, distal end rounded, pedicel usually annulated, short, about 0.062 mm in length, sex cells on one side only of the blastostyle; female gonotheca somewhat kidney-shaped, but markedly narrower at the proximal end, up to 0.75 mm in length and 0.40 mm in width at the widest point, aperture on a tubular projection in the concavity and through which 2 small hydranths emerge; distinct pedicel about 0.093 mm in length and 0.08 mm in width and may be undulated. Locality: Type locality, deep water, in the Minch, Hebrides Id.; Doubtless Bay, 3 nautical miles offshore (Cable Ship “Matai”), 14/8/51, 189; Brothers Is., Cook Strait, on holdfast of Ecklonia about 2 fath. (M. Davidson), 10/5/51, 157. Distribution: Essentially cosmopolitan. Material of this species from off Brothers Island, Cook Strait, is abundant, and there are many fertile stems. These show mostly female gonothecae with the blastostyle at approximately the same stage of maturity (Fig. 10, c). All stems are irregularly and sparsely branched, with the internodes of the main stem often twice the length of those on the branches. Internodes of variable length were a feature of Ritchie's (1911) material from Australia and the present New Zealand specimens show internodes and hydrothecae similar to those described and figured by Ritchie. My material from Doubtless Bay is meagre, a broken stem showing 5 primary hydrothecae and 1 female gonotheca, but these structures have the characters described for H. sessile. Halecium beanii (Johnston, 1838). (Fig. 10, a and b, e–k) 1838. Thoa beanii Johnston, p. 120, Pl VII, Figs. 1 and 2. 1847. Halecium beanii (Johnston), p. 59, Pl. IV, Figs. 1 and 2. 1868. Halecium beanii (Johnston), Hincks, p. 224, Pl. 43, Fig. 2. 1937. Halecium beani (Johnston). Fraser, p. 102, Pl. 20, Fig. 108. Erect stem and main branches polysiphonic when fully grown, up to 12.0 cm in length; internodes very variable in length, in distal monosiphonic region 0.25 to 0.75 mm in length and 0.12 to 0.18 mm in width; in polysiphonic 0.31 to 0.87 mm in length and 0.13 to 0.21 mm in width; node slightly oblique; stem process supporting hydrotheca at distal end of internode; hydrothecal margin very slightly flared; regeneration from primary hydrotheca of common occurrence; hydrothecae with short but distinct pedicels, about 0.06 mm in length: gonotheca—male, oblong oval, 0.62 to 1.0 mm in length and about 0.25 mm in width and with terminal aperture; female “mitten-shaped”, larger than male, 1.12 to 1.25 mm in length and about 0.31 mm in width, aperture lateral, carried on a short neck, 2 small hydranths projecting through the aperture. Locality: Type locality, near Scarborough, in deep water; off Devonport, Auckland (R Kulka), 26/5/50, 549; Woodpecker Bay, West Coast, S.I. (G. Knox), 3/1/52, 396; Chatham Islands, several localities 260–280 fath. (“Chathams Exped. 1954”) Stn. 7, 280 fath. 24/1/54, 550; Stn. 52, 260 fath. 10/2/54, 551; Stn. 59, 290 fath, 11/2/54, 552. Distribution: Essentially cosmopolitan. Stems of specimens from Woodpecker Bay are short and bushy, about 5.0 cm in height, while those from the Chatham Islands are much taller, 12.0 cm in height, and more graceful. Short stems have short internodes both in the monosiphonic and polysiphonic region (0.25 to 0.31 mm in length) and are in every way similar to those described by Fraser for his North American material. The height of stem is close to that recorded by Millard (1957) for the species from South Africa. Tall stems have much longer internodes, 0.56 to 0.75 mm in the monosiphonic regions and 0.75 to 0.87 mm in the polysiphonic. These large colonies are very like those described by Broch (1918). Stems from off Devonport, Auckland, are young, only 1·5 cm in height, but even at this size clearly polysiphonic at the base and with ripe female gonothecae. The internodes are about 0.37 mm in length and 0.10 mm in width in the monosiphonic region. There is, however, insufficient material of the species from New Zealand waters to obtain a good idea of its size range, or to demonstrate if environmental conditions are related to differences in size.

Text-fig. 10—a and b, Halecium beanii (Johnston). a, portion of polysiphonic stem with monosiphonic branch; b, male gonotheca; c and d, Halecium sessile Norman. c, female gonotheca, d, male gonotheca e–k, Halecium beanu (Johnston). e, female gonotheca, Chatham Island material, f, branches from monosiphonic region of erect stem, Woodpecker Bay, South Island; g and h, hydrothecae; i and j, male gonothecae; k, female gonotheca, Woodpecker Bay material.

The bottom material from which the Chathams specimens were taken is described as fine grey, or green, mud-sand, but I have no knowledge of the bottom on which the Woodpecker Bay specimens were growing. However, the rooting stolons from both localities were twisted about tiny black pebbles varying in shape and size, but usually less than 0.05 mm in length and width. These pebbles no doubt give a firmer anchorage in the mud to the rooting stolons. Both male and female gonothecae can be seen on the same branch in one specimen from the Chatham Islands. The male gonothecae are at the distal end of the shoot and the female at the proximal. Millard (1957) also describes this as an occasional feature of Halecium parvulum. Ripe gonothecae occur in January, February and May. Halecium delicatulum Coughtrey 1876. Fig. 11, e, h–n; 12, a–p. 1876. Halecium delicatula Coughtrey, p. 299. 1876a. Halecium delicatulum Coughtrey, p. 26, Pl. III, Figs. 4–5. 1881. Halecium delicatulum Coughtrey, Ridley, p. 103. 1883.? Halecium tenellum var. mediterraneum, Weismann, p. 160, Pl. 11, Figs. 5 and 6. 1888. Halecium flexile Allman, p. 11, Pl V, Fig. 2. —— Halecium gracile Bale, p. 759, Pl. XIV, Figs. 1–3. non H. gracile Verrill, 1874, p. 729. —— Halecium parvulum Bale, p. 760, Pl. XIV, Figs. 4 and 5. 1890. Halecium parvulum Bale Marktanner-Turneretscher p. 218, Pl. 3, Fig. 22. —— No. 16 Halecium sp. Inaba, Figs. 41–45. 1894. Halecium gracile Bale. Clarke, p. 74. —— Halecium gracile Bale, p. 99. 1896. Halecium delicatula Coughtrey Farquhar, p. 461. —— Halecium parvulum Bale. Farquhar, p. 461. 1901. Halecium delicatulum Coughtrey. Hartlaub, p, 368, Pl 21, Figs. 13–15. 1904. Halecium flexile Allman. Thornely, p. 112. —— Halecium flexile Allman. Jaderholm, p. 265. —— Halecium gracile Bale. Jaderholm, p. 266, Pl I, Figs. 2 and 3. 1905. Halecium delicatulum Coughtrey. Hartlaub, p. 613, Fig. 13. 1905 Halecium flexile Allman. Hartlaub, p. 611. 1905. Halecium gracile Bale. Hartlaub, p. 611. 1906. Halecium gracile Bale. Billard, p. 10. 1906a Halecium gracile Bale. Billard, p. 329. 1906b. Halecium gracile Bale. Billard, p. 70. 1907. Halecium gracile Bale. Billard, p. 163. 1910. Halecium flexile Allman. Billard, p. 3. 1911. Halecium flexile Allman. Ritchie, p. 811. —— Halecium gracile Bale. Motz-Kossowska p. 335, Text-fig. VII and VIII. —— Halecium balei Fraser, p. 466. 1913. Halecium delicatulum Bale, Stechow, p. 79. —— Halecium flexile Allman. Stechow, p. 81, Text-figs. 45–49. 1904. non Halecium flexile Allman. Fraser, p. 165, Pl. XX, Fig. 71. —— Halecium flexile Allman. Briggs. p. 286. 1915. Halecium flexile Allman. Bale, p. 246. 1920.? Halecium mediterraneum Weismann. Stechow, p. 34. 1924. Halecium parvulum Bale, p. 235. Halecium delicatulum Coughtrey, Bale, p. 235. 1928. Halecium flexile Allman Trebilcock, p. 6. 1930 Halecium gracile Bale. Totton, p. 145. Halecium flexile Allman Totton, p. 145. 1937. non Halecium flexile Allman. Fraser, p. 104, Pl. 21, Fig. 111. Halecium parvulum Bale. Fraser, p. 107, Pl. 22, Fig. 117. Halecium flexile Allman. Leloup, p. 15. 1938 Halecium flexile Allman var. japonica Leloup. Leloup, p. 4, Text-fig. 1. 1942.? Halecium mediterraneum Weismann. Blackburn, p. 106. 1944. non Halecium gracile Verrill. Fraser, p. 193, Pl. 36, Fig. 171. 1944. non Halecium flexile Allman. Fraser, p. 192, Pl. 35, Fig. 169. 1946. non Halecium flexile Allman. Fraser, p. 73 and 264. 1948. non Halecium flexile Allman. Fraser, p. 22. 1948. Halecium parvulum Bale. Fraser, p. 224. 1950. Halecium flexile Allman. Hodgson, p. 16, Figs. 25–27. 1952. Halecium sp. Ralph, p. 8. 1957. Halecium parvulum Bale. Millard, p. 189, Fig. 4.

Text-fig. 11.—a–d, Halecium fragile Hodgson. e, Halecium delicatulum Coughtrey. After Coughtrey 1876a, Pl. III, Fig. 5, and from Dunedin Harbour: f and g, Halecium (?) tenellum Hincks. Erect stem from Otago Harbour: h–n, Halecium delicatulum Coughtrey. h, from Auckland; i and j, from Nelson; k–m, hydrothecae and hydranths; n, female gonothecae arising from stolon.

Erect stem either polysiphonic or monosiphonic; polysiphonic stems tall, up to 10.0 cm in height, branching usually irregular; monosiphonic stems smaller in size, up to 3.0 cm in height and also irregularly branched; internodes about 0.50 to 0.87 mm in length and 0.10 to 0.18 mm in width; nodes twisted and oblique, sloping alternately in opposite directions; hydrothecae alternate, borne at the distal end of each internode, funnel-shaped 0.050 to 0.075 mm in depth measured from the margin to the line of puncta and 0.14 to 0.19 mm in width at the margin; margin distinctly and markedly flared but in general more so in monosiphonic than polysiphonic growth forms; regeneration from the primary hydrothecae common; pedicels of primary hydrothecae rarely constricted at their origin from the stem, but secondaries, etc., may be; puncta fairly prominent; hydrothecae may show an annular thickening below the diaphragm: gonotheca, female changing in shape from young to mature condition, arising by short smooth or slightly undulated pedicel from the hydrorhiza or the erect stem not terminal on a branch, young female gonotheca compressed squarish in general outline viewed from the broader side, with rounded summit; mature female gonotheca compressed, large 1.0 mm to 1.13 mm in length and about 0.65 mm in greatest width, oval in general outline viewed from the broader side, and usually with a smooth surface, but this may be slightly undulated, central terminal aperture about 0.125 mm in diameter, between two distinct blunt, heavy, tooth-like processes; sporosac oval, 0.75 mm by 0.43 mm approximately and not occupying the whole cavity of the gonotheca, separated from the wall of the gonotheca by a thin chitinous membrane; young male gonotheca pyriform to club-shaped laterally compressed, elongate oval when mature from 0.70 mm to 1.0 mm in height and 0.38 to 0.45 mm in greatest width. Locality: Type locality, Dunedin, Upper Harbour on sponges: Auckland (Marktanner-Turneretscher, 1890, as H. parvulum); Milford, Auckland (R. Kulka), 12/5/50, 556; Narrow Neck, Auckland, drift (P.M.R.), 10/2/53, 359; Wellington Harbour, wharf piles (P.M.R.),—/11/49, 555; Cook Strait, 40–100 fath., Stn. 55 (V.U.C. Zool. Dept.), 23/2/56, 539; French Pass (Hartlaub, 1901); Port Nelson, wharf piles (G. Knox), 4/1/51, 282; Woodpecker Bay, West Coast S.I. (G. Knox), 3/1/52, 392; St Clair, Dunedin, as H. flexile (Trebilcock, 1928); off Otago Heads, 275–300 fath., “Alert” Stn. 54/13 (E. J. Batham), 2/3/54, 543; Bluff, as H. flexile (Trebilcock, 1928). Distribution: Circumpolar in the Southern Hemisphere; Japan; Gulf of Manaar (Ceylon); Indo-China; Morocco. Colonies of Halecium from several North and South Island localities show short (up to 3·0 cm) erect monosiphonic stems with loose irregular branching; nodes twisted obliquely and sloping alternately in opposite directions; the hydrothecal margin strongly everted; and pedicels of the secondary, tertiary, etc., hydrothecae sometimes irregularly pointed. These are the erect stem characters of H. delicatulum described originally by Coughtrey (1876) from Dunedin Harbour and later by Ridley (1881) from Punta Arenas, Hartlaub (1901) from French Pass, New Zealand, and Stechow (1913) from Japan. Ridley's and Hartlaub's material of H. delicatulum was fertile. Their descriptions of the gonothecae, however, differ, but the evidence of the present material points to the conclusion that their material was of a different age, and/or sex. Young male gonothecae on the present material are rectangular to club-shaped in broad view, but when fully grown, elongate oval and about 0.75 mm in length. Young female gonothecae are rounded distally and rather square in general outline viewed from the broader side. When fully grown they are larger than the male gonothecae, about 1·0 mm in length, more or less oval in general outline, and usually with the narrow sides raised into two distinct peaks from the aperture in the depression between them. Colonies from Auckland also demonstrate that gonothecae of H. delicatulum may arise either from the hydrorhiza or the pedicel of the primary hydrotheca on the stem (Fig. 12, a and e). Ridley (1881) describes the gonotheca on his material as “transversely oval in general outline”, and arising from the main stem. This characterisation of the gonothecal shape is somewhat vague and no figure is given, but all in all suggests a young male gonotheca similar to that found on the present specimens of H. delicatulum. Hartlaub (1901) observed and figured gonothecae from French Pass, N.Z., arising from the hydrorhiza, some rectangular in general outline and others with two peaks at the distal end. Hartlaub thought the gonothecae on his specimens were probably male. It is not always possible to determine the sex of very young gonothecae and Hartlaub's “rectangular” gonothecae may have been either male or female, but those with two peaks at the distal end were undoubtedly female.

From the above, Halecium delicatulum Coughtrey, 1876, has the following characters: erect monosiphonic stem with loose irregular branching; nodes twisted obliquely and sloping alternately in opposite directions; hydrothecal margin strongly everted; pedicels of the secondary, tertiary, etc., hydrothecae sometimes irregularly jointed; mature male gonotheca, elongate oval, about 0.75 mm in length; mature female gonotheca about 1.0 mm in length, more or less oval in general outline, with two distinct peaks arising from the narrow sides at the distal end; aperture, in depression between the peaks. In the past H. delicatulum has been regarded as of uncertain specific status, but the more adequate material in the present collection allows a firm decision to be made. It will be shown that Halecium gracile Bale, 1888 (non H. gracile Verrill, 1874), and Halecium parvulum Bale, 1888 and Halecium flexile Allman, 1888 are synonyms of Halecium delicatulum Coughtrey, 1876. Hartlaub (1901) observed the similarity of H. delicatulum and H. gracile Bale and considered the erect stem characters of his New Zealand specimens of the former species identical with those of Bale's species. He regarded the characters of the gonotheca, however, as distinct from those of male colonies of H. gracile and sufficient to separate the two species. Now it has been shown that some at least of Hartlaub's specimens of H. delicatulum were female in sex and that the fully grown gonothecae of this species possesses two distal peaks with the aperture in the concavity between them similar to that known for H. gracile Bale, 1888, the latter species becomes a synonym of H. delicatulum Coughtrey, 1876. Furthermore, the male gonothecae of H. gracile and H. delicatulum are now known to possess the same characters. H. gracile has long been considered the monosophonic growth phase of H. parvulum Bale, 1888, a species described as possessing a polysiphonic erect stem. Bale himself (1924, p. 235) so regarded H. gracile, and also recognised H. gracile and H. parvulum as synonyms of the taller and larger polysiphonic H. flexile Allman, 1888. Through the courtesy of the British Museum (Natural History) and the National Museum of Victoria, Australia, I have been able to examine material of the above three species and compare it with material here recognised as H. delicatulum. From the evidence of all this material, which covers a wide range of latitudes (Antarctic to subtropical waters), it must be concluded that H. gracile Bale, H. parvulum and H. flexile are synonyms of H. delicatulum. It is realised that the female gonotheca of H. flexile is not known, but the complete similarity of internode, node, hydrotheca and male gonotheca of H. delicatulum and H. flexile leaves little doubt that the latter species is a synonym of H. delicatulum. It is not yet clear what factors cause the readily distinguishable differences in growth form and size. In erect stems of both growth forms, however, and in short and tall stems, branching is irregular, the nodes twisted and oblique, sloping alternately in opposite directions; and the hydrothecae funnel-shaped, 0·05 to 0·075 mm in depth, margin to line of puncta and with a strongly flared margin. Male and female gonothecae change shape during growth; mature male gonothecae somewhat compressed and elongate oval in shape; mature female with two prominent distal peaks with the terminal aperture in the groove between them. In general, material assigned by other workers to “H. gracile” Bale (non H. gracile Verrill), “H. parvulum” Bale and “H. flexile” Allman appears to possess characters that fall within the present concept of H. delicatulum and therefore to be regarded as synonyms of the latter species. Fraser's (1914 et sequi) North American material of “H. flexile”, however, is regarded here as exceptional and its status is discussed below. Millard (1957, p. 190) recognises a large variety of “H. parvulum”, H. parvulum var. magnum Millard, in which the erect stem height, hydrotheca and male gonothecal length and shape are similar to the type material of “H. flexile” Allman. Also Millard's Fig. 4B of this varietal form shows a “pseudodiaphragm” like that figured by Leloup (1938) for “H. flexile var.

japonica”. A similar pseudodiaphragm is seen as an occasional feature in the hydrothecae of some material in the present collection of H. delicatulum and is figured by Hartlaub (1901, Pl. 21, Fig. 15) for his New Zealand material of H. delicatulum from French Pass. As noted above, Fraser's North American material of “H. flexile” does not seem to be a synonym of H. delicatulum. Fraser first assigned North American material from Nanoose Bay, off West Rocks, Vancouver Island region, to H. flexile in 1914, and commented, “this species seems to have got rather far afield as the nearest point at which it has been reported is off Patagonia, but the resemblance to Allman's figure is so marked that there can scarcely be any doubt that it is the same species”. The available evidence, however, suggests that there is quite some doubt that Fraser's material is H. flexile Allman as generally recognised. The most striking difference between Fraser's North American material and that described by Allman for “H. flexile” from Marion Island and shown by other Southern Hemisphere material is the habit of the erect stem. North American specimens have a stiff, erect polysiphonic stem with regularly pinnate branches that are themselves rarely branched and run to the extremity without forking, whereas high latitude tall polysiphonic Southern Hemisphere specimens show the erect stem with irregular but profuse branching which gives the colony a loose, bushy appearance (Fig. 12, p). The stems differ also in structure. In Fraser's material the nodes are straight, not twisted and oblique sloping alternately in opposite directions, and the hydrophore margin shows less flare than in other material formerly recognised as H. flexile. The evidence strongly supports the conclusion that Fraser's North American material is a distinct species similar to H. flexile in possessing a polysiphonic stem but otherwise differing in general stem habit, nodal and hydrothecal characters. The assumption that Fraser's specimens of “H. flexile are distinct from others formerly included in that species is strengthened by the fact that Fraser recognised “H. parvulum” Bale as a separate species. This latter species, now shown to be a synonym of H. delicatulum Coughtrey, has in the past been generally recognised as a synonym of “H. flexile” Allman. Material assigned by Fraser to “H. flexile” is described below in more detail under the name of H. fraseri nom. nov. In summary, the available evidence points to H. gracile Bale, H. parvulum Bale and H. flexile Allman of authors, except H. flexile Fraser (1914, et sequi), as synonyms of H. delicatulum Coughtrey. Two other species of Halecium—viz., H. mediterraneum Weismann, 1883, and H. antarcticum Vanhöffen, 1910, known to me only from the literature, are probably also synonyms of H. delicatulum. “H. flexile” is sometimes recognised as a synonym of H. mediterraneum, and Totton (1930, p. 145) regards H. antarcticum a closely allied if not identical species to “H. flexile” but retains them as separate species as neither the mature male nor female gonothecae of H. antarcticum is known. Halecium fraseri nom. nov. for Halecium flexile Allman as recognised by Fraser (1914, et sequi) 1914. Halecium flexile Allman. Fraser, p. 165, Pl. XX, Fig. 71. 1937. Halecium flexile Allman. Fraser, p. 104, Pl. 21, Fig. 111. 1944. Halecium flexile Allman. Fraser, p. 192, Pl. 35, Fig. 169. 1946 Halecium flexile Allman. Fraser, p. 73 and 264. 1948. Halecium flexile Allman. Fraser, p. 222. Erect stem rather small but up to 5.0 cm in height; polysiphonic, branched; branches short (about 12.0 mm), distinctly and regularly pinnately arranged, giving little spread to the plumose colony: rarely themselves branched; internodes about 0.75 mm in length and about 0.20 mm in width; nodes transverse; no joint between the internodal process of the stem and the pedicel of the first hydrotheca in the series; length of the pedicel or the pedicel and the process together about 0.25 mm, hydrotheca about 0.05 mm in depth, and margin with only slight flare: gonotheca, male, oval or obovate with a distinct pedicel arising just at the point where the pedicels of the hydrophores are given off; female gonotheca unknown. (Data from Fraser, 1944 and 1946.)

Text-fig. 12.—a–p, Halecium delicatulum Coughtrey. a–e, female gonothecae at various stages of development; f–k, male gonothecae at various stages of development; 1–0, from British Museum material of “Halecium flexile” here recognised as H. delicatulum; p, erect stem of “H. flexile” after Allman Pl. V, Fig. 2; q, Halecium expansum Trebilcock.

Locality: Type locality, Nanoose Bay, off West Rocks, Vancouver Island region, Canada. This species is not known from New Zealand. Distribution: Eastern Pacific from Moresby Island, Q.C.I., to San Juan Archipelago; in western Atlantic, from Narragansett Bay, 5–110 fathoms. The measurements are calculated from Fraser's (1944) Pl. 35, Fig. 169. The small size of the figure makes accurate measurement difficult. The choice of “Type locality” is that of the present writer and is the first named locality given for the species by Fraser in 1914, p. 165. Halecium fragile Hodgson, 1950. Fig. 11, a–d. 1950. Halecium fragile Hodgson, p. 15, Figs. 25–27. Hydrorhiza a creeping, filiform stolon, smooth or irregularly undulated, 0.03 to 0.07 mm in diameter; erect stem, flexuous, monosiphonic, simple or sparingly branched, up to 5.0 mm in height; internodes smooth, cylindrical, or sometimes with irregular constrictions 0.37 to 1.66 mm in length, 0.05 to 0.09 mm in diameter; branches alternate, arising from a small lateral process below the primary hydrotheca; hydrotheca tubular, expanding from region of puncta to margin, 0.036 to 0.062 in depth; margin smooth, strongly everted; diameter of aperture 0.12 to 0.19 mm; regeneration of primary hydrotheca common, secondary and tertiary, etc., arising from the region of puncta of its predecessor: gonotheca unknown. Locality: Type locality, D'Entrecasteaux Channel, Tasmania; Motuihi Channel, Auckland, on Synthecium elegans Allman (R. Kulka), 21/8/49, 557. Distribution: Tasmania, New Zealand. H. fragile has the thinnest stem of any New Zealand halecid, and although the gonotheca is still unknown the stem characters are sufficiently distinctive to separate out the species. The 2·0 cm portion of host hydroid stem on which my specimens of H. fragile were growing is completely covered with the tangled mass of stolons and erect stems. The stems on the whole have not as many branches as Hodgson's Tasmanian specimens, but otherwise the hydrothecal and stem dimensions are similar to those described for the species by Hodgson. Halecium (?) tenellum Hincks, 1861. Fig. 11, f and g. 1861. Halecium tenellum Hincks, p. 252, Pl. VI, Figs. 1–4. 1868. Halecium tenellum Hincks, p. 226, Pl. XLV, Fig. 1. 1957. Halecium tenellum Hincks. Millard, p. 193, Fig. 5. Erect stem delicate and small, up to 4.0 mm in height, branched and branches typically sympodial but may arise in pairs; proximal and distal ends of internodes annulated, otherwise smooth; stem internodes of irregular length 0.25 to 0.70 mm and 0.10 to 0.12 mm in width; a varying number up to 7 of the proximal stem internodes without hydrothecae; hydrothecae 0.03 to 0.04 mm in length margin to line of puncta, 0.12 to 0.18 mm in diameter at the margin; margin everted; secondary hydrothecae, etc., with basal annutations; (?) male gonotheca, “flattened in plane at right angles to stem, oval to circular in front view (very similar to those figured by Broch), borne on short stalk which may be segmented, from stem or hydrorhiza”(Millard, 1957). Locality: Type locality, Salcombe Bay, Devon; Goat Island, Otago Harbour (B. Brewin), 2/12/44, 447. Distribution: Essentially cosmopolitan. There is only one infertile stem of this species in the present collection from Otago Harbour, and although it shows the characters described for H. tenellum Hincks the material is inadequate to give a firm decision on its status and the species is recorded with a query. It has not been taken previously from our waters. Halecium expansum Trebilcock, 1928. Fig. 12, q; 13, a. 1928. Halecium expansum Trebilcock, Proc. Roy. Soc. Vict. XLI (1): p. 7, Pl. III, Fig. 2–2c; Pl. IV, Fig. 2–2b. 1932. Halecium expansum Trebilcock. Leloup, p. 145, Pl. XVII, Fig. 2. Erect stem small, about 6.0 mm, usually monosiphonic but main stem may be strengthened by one or two irregular peripheral tubes, irregularly sympodial, axis often develops as strongly as the branch; branching not in any one plane, often active in distal region giving a “bushy mass”, also may be falsely dichotomous; primary hydrotheca sessile, about 0.16 mm wide and 0.031 mm deep; secondary hydrothecae with large basal cavity about 0.16 mm wide and 0.187 mm long, hydrotheca wide (about 0.16 mm), shallow (about 0.031 mm) and expanding distally, thick walls, margin not everted; “puncta” inconspicuous: diaphragm well developed with large aperture about 0.062 mm wide, an internode of irregular outline arising from the inner margin of the diaphragm, separates primary, secondary hydrothecae, etc., is about 0.31.

mm long by 0.093 mm wide, and in the distal actively growing regions of the colony the internode may be strengthened by complete or incomplete chitinous bands; regeneration from primary hydrotheca fairly common; hydranth with about 15 tentacles: gonothecae unknown. Locality: Type locality, St. Clair, Dunedin, on roots of algae in rock pools; Portobello Marine Biol. Stn., reef, Dunedin Harbour, on ascidian Cnemidocarpa cerea (B. Brewin), 20/9/44, 449. Distribution: New Zealand, and? Gulf Stream on Sargassum. This is a rare species, known for New Zealand only from the intertidal region in the Dunedin area and elsewhere from the Gulf Stream on Sargassum (Leloup, 1932). So far all specimens have been infertile. Two complete stems 6.0 mm high, and two broken stems about 4·0 mm high in the present collection, are similar to those previously described by Trebilcock from St. Clair, Dunedin. Genus Hydrodendron Hincks, 1874 1868 Ophiodes Hincks, p. 230. 1888. Diplocyathus Allman, p. 16. 1919. Ophiodissa Stechow. Nematothecae present, distributed variously on the stem and branches, and below each hydrotheca; hydrothecae usually too small to lodge the contracted hydranths and usually the same diameter at the base as the supporting pedicel; margin entire; secondary and tertiary hydrothecae, etc, arising in various ways, either from the side of the primary, or from within; hydranths with conical proboscis; reproductive zooid producing a fixed sporosac. Blackburn (1938) reviews the status of Ophiodes Hincks, Hydrodendron Hincks, Diplocyathus Allman and Ophiodissa Stechow, and demonstrates that Hydrodendron Hincks, 1874, is the valid genus for species with the above characters. Species of this genus known from New Zealand—viz., H. armata Totton and H. caciniformis (Ritchie) (a new record for N.Z.), are rare species, with the former described only from 40–300 fathoms in our waters. Key to the New Zealand Species of Hydrodendron 1 (2) Erect stem polysiphonic; nematothecae on accessory tubes and on the proximal part of each internode on the side opposite the hydrotheca, others scattered irregularly; hydrotheca shallow, primarily sessile, margin not everted, and at markedly oblique angle to axis of internode: gonothecae aggregated loosely together. Hydrodendron armata Totton, 1930 2 (1) Erect stem polysiphonic; nematothecae conspicuous, “vase-shaped” but not numerous arising from the sides of the primary and secondary hydrothecae; hydrothecae deep, with distinct pedicel, secondary hydrothecae arise from lateral region of pedicel of primary; both primary and secondary hydrothecae with hydranths; margin of hydrothecae everted; gonotheca unknown. Hydrodendron caciniformis (Ritchie, 1907) Hydrodendron armata (Totton, 1930). Fig. 13, d–i; 14, b–d. 1930. Ophiodissa armata Totton, p. 142, Text-fig. 2b. Erect stem polysiphonic up to 9.0 cm in height; branched, branching mostly in one plane; nematothecae tiny shallow saucer-shaped, found on the accessory tubes, on the proximal part of the internode opposite the hydrotheca and others scattered irregularly; internodes 0.50 to 0.76 mm in length on monosiphonic regions of the stem, and about 0.18 mm in width; hydrothecae very shallow, about 0.031 mm in depth measured from the margin to the line of puncta; 0.16 to 0.18 mm in width at margin; margin smooth, sloped obliquely; primary hydrotheca sessile: gonothecae loosely aggregated into a scapus, about 20 × 15 mm; delicate branches of the scapus bear closely packed paired gonothecae and scattered nematophores; gonothecae “curving sharply backwards and terminating in a hook-like process at the extremity of which is the gonothecal mouth”; about 0.68 mm in length excluding the backwardly curved region and 0.43 mm in greatest diameter.

Locality: Type locality, “Terra Nova” Stn. 91, off Three Kings Is., New Zealand, 300 fath.; Cook Strait, 40–100 fath. Stn. 55 (V.U. Zool. Dept.) 23/2/56, 521. (Known only from New Zealand.) There are five tall stems about 9.0 cm, almost twice the height of Totton's original material, in the present collection from Cook Strait. One stem is fertile, thus extending our knowledge of the species. The scapus is a subspherical mass about 20 × 15 mm and the gonothecae are similar in size and shape to those described by Hickson and Gravely for “Halecium aborea” (Allman) from the Antarctic. H. armata is a closely allied if not a varietal form of the latter species. H. aborea is taller than H. armata, up to 25·0 cm in height, with larger nematothecae restricted to the proximal part of the internode opposite the hydrotheca, a deeper hydrotheca, and with a greater length of hydrothecal wall free from the stem. The gonothecae as noted are similar. It seems likely that as more is known of these two species the differences now apparent will prove to be of no significance for specific separation; they could well be due to the material being taken from localities widely separated in latitude—i.e., New Zealand, Three Kings Islands and Cook Strait, and the Antarctic (Kerguelen, McMurdo Sound, etc.). Hydrodendron caciniformis (Ritchie, 1907). Figs. 13, b and c; 14, a. 1907. Ophiodes caciniformis Ritchie, p. 500, Pl. XXIII, Figs. 11 and 12; Pl. XXIV, Fig. 1. 1919. Ophiodissa caciniformis (Ritchie). Stechow, p. 42. ? Ophiodes australis Bale, p. 336, Pl. XVI, Fig. 1. 1935. Diplocyathus caciniformis (Ritchie). Leloup, p. 10. 1957. Hydrodendron caciniformis (Ritchie). Millard, p. 186, Fig. 3. Colony up to 2.0 cm, probably more, in height, hydrorhiza a network of stout tubes becoming more or less fascicled; hydrocaulus straight, polysiphonic, branches short, about 5.0 mm in length, straight and usually monosiphonic; internodes 0.43 to 0.75 mm in length and 0.125 to 0.25 mm in breadth; nodes straight, or slightly oblique; hydrothecae arising from the distal region of the internode; primary hydrothecae alternate, borne on very short processes of the internode (about 0.093 to 0.14 mm in length), pedicel of hydrotheca more or less cylindrical, 0.125 mm length and 0.093 mm wide, hydrotheca slightly expanding up to 0.25 mm at the margin, and with a large basal chamber; puncta conspicuous, 0.04 to 0.062 mm from the margin; diaphragm, 0.09 to 0.12 mm from the margin; secondary hydrothecae arise from the lateral region of the pedicel of the primary, a series of up to three may occur, each arising from the pedicel of the preceding hydrotheca; nematothecae not numerous, from 0.125 to 0.187 mm in length and about 0.062 mm in width, rather “goblet-shaped” with everted margin; nematothecae from the bases of the hydrothecae, “from hydrorhiza” (Millard, 1957) and from stem internodes: gonotheca not known. Locality: Type locality, Cape Verde Islands; 10 miles N.W. Cape Maria van Diemen (G. Knox),—/—/—, 416. Distribution: Cape Verde Islands, West Indies, Mediterranean, South Africa, New Zealand. The New Zealand material contributes further to our knowledge of the stem characters of this relatively rare species. All previous accounts describe the species as small, the tallest known stems being 9.5 mm in height and from South Africa (Millard, 1957, p. 186). Some of Millard's specimens are also “weakly fascicled at (the) base” (Fig. 3A). The present specimen is much taller (22.0 mm) and shows that when fully grown the stem may be strongly fascicled. The description in this paper of H. caciniformis is made from the distal region of a broken stem 22·0 mm in length from Cape Maria van Diemen. About 17·5 mm of this length is polysiphonic, the rest monosiphonic. The proximal polysiphonic region is 0·68 mm in diameter, and the main stem is surrounded by about 4 accessory tubes. Stem internodes are somewhat wider and longer than Millard's South African material, and this is probably accounted for by the fact that the present specimen, although not a complete stem, is just over twice the length of Millard's tallest stem. Branching is alternate and regular, with 2 stem hydrothecae between each branch. Measurements of the hydrothecae and nematothecae in the New Zealand material are similar in range to those given by Millard. The false diaphragm figured by him.

Text-fig. 13.—a, Halecium expansum Trebilcock. b–c, Hydrodendron caciniformis (Ritchie). d–i, Hydrodendron armata Totton h, portion of scapus showing gonothecae and nematophores; i, single gonotheca.

(1957, Fig. 3, B and C) is shown by the main stem hydrothecae and by the proximal branch hydrothecae in the present specimen but is not evident in other hydrothecae. The strongly fascicled tall stems up to 50·0 mm of H. australis described and figured by Bale (1919) are strikingly similar to the present stem of H. caciniformis. H. australis (Bale) is here, however, queried as a synonym of H. caciniformis as the hydrothecae of H. australis (Bale, 1919, Pl. XVI, Fig. 1) are shallower, measured from the margin to puncta line, than those of H. caciniformis, and the gonotheca of the latter is unknown. The gonotheca of H. australis is “barrel-shaped or nearly cylindrical above, tapering below, summit broad or flat; borne on the hydrorhiza”. Family Syntheciidae Marktanner-Turneretscher, 1890 Erect stem monosiphonic; hydrothecae without a pedicel and fused to the stem or branch by part of their adcauline side; alternate, or in opposite pairs; margin entire; no operculum; diaphragm present: gonothecae pedicellate, arising from the interior of a hydrotheca, or from below the hydrotheca on stem or branch; reproductive zooid producing a fixed sporosac. The above concept of the family is that of Billard (1925, p. 121). Therefore the genus Stereotheca with toothed hydrothecal margin which has in the past been included within the family by some writers on New Zealand hydroids (Bale, 1924, pp. 251–52), is recognised as a member of the family Sertulariidae. The only genus of the F. Syntheciidae known from New Zealand waters is Synthecium. Although material of this family in the present collection has been taken from many localities in both the North and South Islands it can with certainty be placed in only two species—viz., Synthecium elegans Allman and C. carinatum Totton, but there is evidence that another species previously described from New Zealand is a synonym of S. elegans. This is S. ramosum Allman. S. tottoni (nom. nov. for S. robustum Totton) and S. longithecum Totton are recognised here as distinct species, although they show several features similar to S. elegans forma elegans. Furthermore, the differences between them and the latter species could be due to material being taken from different localities or being of a different sex. S. tottoni and S. longithecum are, however, known to me only from the literature and no firm decision can be given on their status at present. S. campylocarpum Allman is also recognised as a distinct species, not a synonym of S. patulum Busk. Genus Synthecium Allman, 1872 Erect stem monosiphonic; hydrothecae without a pedicel and fused to the stem or branch from ½ to ¾ of the adcauline side, hydrothecae in opposite pairs, margin entire, no operculum; diaphragm present: gonothecae arising from the interior of a hydrotheca. It is the common experience here as elsewhere that species of this genus are difficult to separate, as not only does size in male and female colonies frequently differ and infertile material be easily misidentified, but stems of different species may be very similar in size and general appearance. All the New Zealand specimens of Synthecium examined can be placed in one of two size groups. First, specimens with a tall, erect stem up to 7·0 cm in height; large hydrothecae, 0·80 mm to 1·0 mm in overall length, and where known, large gonothecae up to 1·4 mm in length, exclusive of the pedicel; and secondly, specimens with smaller erect stems up to 5·0 cm in height; small hydrothecae about 0·50 mm in overall length, and where known, small gonothecae about 0·80 mm in length. Material with small stems and small hydrothecae, etc., can be readily further separated into two groups—i.e., specimens with an internal adcauline hydrothecal tooth and specimens without this tooth. S. carinatum is unique among known New Zealand species of Synthecium in possessing an internal hydrothecal tooth. Therefore small stems from Doubtless Bay, North Auckland, with such a tooth and showing the other erect stem characters of S. carinatum, although infertile, are here recognised as that species. Other specimens from several localities possessing small stems.

Text-fig. 14—a, Hydrodendron caciniformis (Ritchie). Portion of erect stem from monosiphonic region: b–d, Hydrodendron armata Totton. b, portion of erect stem from monosiphonic region; c, nematotheca; d, female gonothecae dissected out from scapus. and small hydrothecae without an internal tooth have the characters described by Bale (1914a, p. 5, Pl. I, Figs. 3–5) for S. subventricosum, a species not previously known from New Zealand. It will be shown below that S. subventricosum is a small form of S. elegans, regarded here as S. elegans forma subventricosum Bale. All tall colonies in the present collection are recognised as S. elegans. These colonies are regularly branched with at least ⅔, usually more, of the main stem internodes showing two pairs of hydrothecae and a pair of opposite pinnae and gonothecae somewhat compressed with prominent flared ridges meeting in a zig-zag line on the narrow sides (Fig. 17, a). The plane of opening of the hydrotheca is variable, sometimes more or less oblique and at others almost vertical (Fig. 17, c–e). Hydrothecae with either plane of opening may occur on the one erect stem. Similarly, the width of aperture and the length of the free adcauline hydrothecal wall is variable (Fig. 17, b). Tall colonies from Otago Heads and Auckland demonstrate that the number of gonothecal ridges and the length to breadth ratio differs in young and old gonothecae. Young gonothecae when viewed from the broader side are usually subspherical with 3 to 4 ridges and a length to breadth ratio about 1:1. As the gonothecae grow, the.

number of ridges increases up to 8, although 7 is the average number found on the largest gonothecae. The length to breadth ratio varies from 1—½: 1 to 2:1. The present material of S. elegans is of value in determining the specific status of S. ramosum, a species which is frequently regarded as a synonym of S. elegans (Billard, 1925, p. 130; Bale, 1924, p. 251), although Totton (1930), while recognising the close similarity of the two species, considers the hydrothecae of the holotype of S. ramosum differ from those of S. elegans in having a larger free adcauline wall, a wider orifice, and a plane of opening less nearly vertical. Tall New Zealand colonies of Synthecium now show that these characters are variable and therefore unreliable for separating S. ramosum from S. elegans. S. ramosum is regarded here as a synonym of S. elegans forma elegans. It is anticipated that as more data becomes available on the growth form assumed by species of Synthecium in differing environmental conditions in New Zealand, need for further classificatory changes will be evident. Key to the Species of Synthecium in New Zealand 1 (2) Hydrothecae with internal tooth S. carinatum Totton, 1930 2 (1) Hydrothecae without internal tooth. 3 (6) Hydrothecae about 0.50 mm to 0.62 mm in overall length. 4 (5) Gonothecae elongate pod-shaped with 7 to 10 transverse ridges with narrow flare, and ridges not meeting in a zig-zag on the narrow sides S. campylocarpum Allman, 1888 5 (4) Gonothecae compressed, about 0.80 mm in length excluding the pedicel, with up to 8 usually 6 to 7 prominent transverse ridges with a wide flare and ridges meeting in a zig-zag line on the narrow side; aperture raised on a cone-shaped structure S. elegans Allman, 1872 forma subventricosum Bale, 1914 6 (3) Hydrothecae much larger, up to 1.6 mm in overall length. 7 (10) Hydrothecae adnate to the stem for about ⅓ of its length. 8 (9) Hydrothecal aperture variable, sometimes nearly vertical to the longitudinal axis, at others oblique; gonothecal shape and structure as for S. elegans forma subventricosum but larger up to 1.4 mm in length S. elegans Allman forma elegans 9 (8) Hydrotheca strongly curved outwards so that aperture is nearly vertical: gonotheca unknown S. longithecum Totton, 1930 10 (7) Hydrotheca attached to stem for about ¾ of length: gonotheca ovoid, compressed, 11 to 12 transverse thickened folds S. tottoni (Totton, 1930) nom. nov. S. robustum Totton. Synthecium carinatum Totton, 1930. Fig. 15, a and b. 1930. Synthecium carinatum Totton, p. 171, Fig. 24. Erect stem monosiphonic, up to 4.0 cm in height; branched, branches usually regularly and pinnately arranged; hydrothecae curving gradually away from the axis so that the plane of orifice makes an angle of about 20° with the axis, axial wall of hydrotheca generally flattened, in some hydrothecae on the distal adcauline wall is a well-marked keel-like internal tooth, and occasionally traces of 2 lateral internal teeth on the abcauline side, fused part of hydrotheca 0.29 mm in length, free part 0.12 mm, diameter at the orifice 0.11 mm; banana-shaped nematocysts 0.05 × 0.01 mm are scattered through the ectoderm of the hydrocaulus and the distal part of the gonophores, 10 to 12 also present in the bases of some of the polyps: gonotheca with folded walls, much flattened in a plane at right angles to the plane of branching; folds 12 in number, proximal 2 or 3 circular, others coalesce at the edges, where they are either opposite, sub-opposite or alternate; gonothecae 0.83 to 1.02 mm in length, 0.64 mm in breadth, and 0.27 mm in thickness. Locality: Type locality, Spirits Bay, near North Cape, 11–20 fathoms; off Cape Maria van Diemen, 35–40 fath. (Totton, 1930); Doubtless Bay, 3 nautical miles offshore—on submarine cable (Cable Ship “Matai”), 14/8/51, 187.

The present material from Doubtless Bay is meagre compared with Totton's taken about 50 miles further north near North Cape, as it consists only of an incomplete stem 6·0 mm long with a branch span of 12·0 mm and 2 small branches about 7·0 mm in length. There is, however, little doubt concerning the identity of this material with S. carinatum, as 16 hydrothecae of the 34 present on the small branches show very clearly the internal adcauline tooth and one hydrotheca also shows a single abcauline tooth. These hydrothecal features are characteristic of S. carinatum. S. carinatum is known at present only from New Zealand. Synthecium campylocarpum Allman, 1888. Fig. 15, c–g. 1888. Synthecium campylocarpum Allman, p. 78, Pl. XXXVII, Fig. 1. 1890. Synthecium campylocarpum Allman. Marktanner-Turneretscher, p. 248. 1896. Synthecium campylocarpum Allman. Farquhar. p. 466. 1913. Synthecium campylocarpum Allman. Stechow, p. 127. 1919. Synthecium campylocarpum Allman. Jaderholm, p. 14. 1924. Synthecium orthogonium (Busk). Bale, p. 250 (synonymy). 1930. Synthecium campylocarpum Allman. Totton, p. 169. Erect stems monosiphonic, pinnately or bipinnately branched, attaining a height of about 5.0 cm; stem jointed; internodes long (2.00 to 2.33 mm in length, 0.25 to 0.33 mm in width), usually bearing a single pair of hydrothecae near the middle, and a pair of opposite pinnae near the distal end, but this arrangement may vary and 2 or 3 pairs of hydrothecae may be present on the stem internode, or they may be entirely wanting from these internodes; pinnae distant, at an angle of about 70° to the stem axis; nodes usually well defined; hydrothecae opposite, not in contact with each other, tubular, overall length 0.50 mm to 0.68 mm, adnate about ¾ of length, free portion 0.17 mm to 0.25 mm; free portion divergent, ascending; aperture circular, diameter 0.17 to 0.18 mm; margin entire, sinuated, slightly everted and may be regenerated once or twice; gonotheca, elongate pod-shaped, slightly compressed, with 7 to 10 slightly flared transverse ridges not meeting in a zig-zag line on the narrow sides; about 1.25 mm in length and about 0.56 mm in greatest diameter. Locality: Type locality, off Port Jackson, Australia; Auckland (Marktanner-Turneretscher, 1890). Distribution: New Zealand; Ternate;? Tahiti; Queensland, Australia. No New Zealand material has come to hand which can be identified as S. campylocarpum although specimens of Synthecium have been taken in the Auckland area from where the species was originally recorded from our waters by Marktanner-Turneretscher (1890). The only specimens in the present collection from the Auckland area are clearly recognisable as varietal forms of S. elegans Allman. The above description of S. campylocarpum is based on material kindly sent me by Miss Pamela Pennycuik, and dredged in 7 fathoms off Myora, Queensland, Australia. This material, which consists of a complete stem 5·0 cm in height and two incomplete stems 3·0 cm and 2·0 cm in height, is readily identified as a female colony of S. campylocarpum Allman, and the stem and gonothecal features distinguish it from other material of Synthecium in the present collection. As far as can be ascertained it is also similar to the specimens described from Auckland by Marktanner-Turneretscher (1890) as S. campylocarpum. The systematic position of S. campylocarpum is, however, uncertain. Billard (1925) recognises it as a synonym of S. patulum, and others (e.g., Bale, 1924) a synonym of S. orthogonium. In view of Totton's findings on the type material of S. patulum, S. orthogonium and S. campylocarpum, it seems best for the present to regard these species as distinct. Synthecium elegans Allman, 1872 forma subventricosum Bale, 1914. Fig. 16, a–h. 1914a. Synthecium subventricosum Bale, p. 5, Pl. I, Figs. 3–5. 1942. Synthecium elegans Allman. (In part.) Blackburn, p. 111. Erect stem similar to forma elegans, but about half the size; internodes of main stem very similar in proximal and distal regions, 1.62 mm to 2.25 mm in length and 0.21 mm to 0.25 mm in diameter; hydrotheca with adnate region 0.30 mm to 0.33 mm in length, free portion 0.13 to 0.19 mm in length; diameter of hydrotheca at margin 0.13 to 0.19 mm: gonotheca as for forma elegans, but only up to 0.80 mm in length excluding the pedicel. Locality: Type locality, Great Australian Bight, 40–100 fath., type specimens National Museum of Victoria, Melbourne, Australia; off Cape Maria van Diemen, 10 miles N.W., 50

Text-fig. 15.—a and b, Synthecium carinatum Totton. c–g, Synthecium campylocarpum Allman. (Drawn from Queensland specimen.)

fath. (G. Knox), —/—/—, 419; Whatipu, Auckland (C. Trevarthen), —/3/50, 485, Cook Strait, 40 fath. (N.Z. Geol. Survey Dept.), 27/8/50, 153; St. Clair, Dunedin (drift), (R. Kulka), 25/2/51, 533. Distribution: Australia, New Zealand. Through the courtesy of the National Museum of Victoria, Australia, I was able to compare Bale's material of S. subventricosum with my small colonies of Synthecium in which the hydrothecae lacked an internal adcauline tooth. Although the base of the hydrotheca in my New Zealand specimens is not quite as regularly swollen, as in the Australian specimens, they are undoubtedly recognisable as the same species Bale (1914) described as S. subventricosum. Nevertheless, apart from the smaller size of the hydrotheca and gonotheca, both Bale's and the present New Zealand specimens of S. subventricosum are similar to S. elegans Allman and here considered a small variety of this species. Size in this instance does not, however, seem related to the sex of the colony as is frequently the case in species of Synthecium (Totton, 1930, p. 168). The sex of all the present material of S. elegans, whether it possesses large hydrothecae and large gonothecae or small hydrothecae and small gonothecae, appears to be female. In several gonothecae, eggs have been fertilised and cleavage well advanced (Fig. 16, d). It is not yet apparent if size is related to environmental conditions I agree with Billard (1925, p. 129) that S. subventricosum is a synonym of S. elegans but because the size difference is constant recognise the smaller form of S. elegans as S. elegans forma subventricosum. Both the New Zealand and Australian material of S. elegans forma subventricosum demonstrates that the subalternate arrangement of the hydrothecae described by Bale (1914, p. 5, Pl 1, Fig. 3) is associated with anastomoses between the distal pinnae of many stems of a colony and/or regeneration after a break. Anastomes between pinnae is of common occurrence in New Zealand specimens of forma subventricosum Furthermore, there is evidence that the ova found in some hydrothecae by Bale and thought by him to be deposited there by “some animal” are in reality the ova of S. subventricosum. In Bale's material and in the present New Zealand material the presence of eggs in the hydrotheca seems to have been brought about by the breaking away of the gonotheca at the level of the hydrothecal aperture, with the consequent scattering of contents, some of which fell into the hydrotheca from which the gonotheca took its origin. The remains of a gonothecal stalk can usually be seen within those hydrothecae that contain eggs. Synthecium elegans Allman, 1872, forma elegans. Fig. 17, a–e. 1872. Synthecium elegans Allman, p. 229, Fig. 1. 1875. Synthecium elegans Allman. Coughtrey, p. 285. 1876. Sertularia elegans (Allman). Coughtrey, p. 301. 1876a Sertularia elegans (Allman). Coughtrey, p. 29. 1876a. Synthecium elegans Allman. Allman, p. 266, Pl. XV, Figs. 1–3. 1885. Synthecium ramosum Allman, p. 137, Pl. XII, Figs. 3–4. 1896. Synthecium elegans Allman. Farquhar, p. 465. (Synonymy). Synthecium ramosum Allman. Farquhar, p. 465. (Synonymy). 1898. Synthecium elegans Allman. Hilgendorf, p. 211, Pl XX, Figs. 3, 3a. 1901. Synthecium elegans Allman. Hartlaub, p. 368. 1924. Synthecium elegans Allman. Bale, p. 251. (Synonymy.) 1925. Synthecium elegans Allman. Billard, p. 129, Fig. 5. 1930. Synthecium elegans Allman. Totton, p. 168, Fig. 22 a and b. Synthecium ramosum Allman. Totton, p. 170, Fig. 23. 1942. Synthecium elegans Allman. (In part.) Blackburn, p. 111. (Synonymy.) Erect stem monosiphonic, up to 15.0 cm in height; branched, branches opposite, usually regularly and pinnately arranged; nodes of main stem and branches often indistinct; basal internodes of main stem may or may not show hydrothecae; frequently only a pair of opposite pinnae, at least ⅔ of the other main stem internodes with 2 pairs of hydrothecae about the middle of the internode and a pair of opposite pinnae at the extreme distal end; proximal internodes of main stem from 4.25 mm in length, 0.50 mm in width and distal 2.35 mm in length and 0.30 mm in width; secondary branching and anastomosing may occur; hydrothecae paired, borne on the stem and branches, in the main strictly opposite, but the first proximal.

Text-fig. 16—a-h, Synthecium elegans forma subventricosum Bale. a–e and h, from New Zealand waters; f and g, from type specimen of “Synthecium subventricosum”.

pair (as is general in the family) of the branch, subopposite, the adcauline member being the closest to the main stem; hydrothecae rather cylindrical, margin smooth, often everted and multiple, aperture more or less circular, 0.25 to 0.31 mm in diameter; adnate to the internode up to ⅔ of the adcauline length (0.75 to 0.86 mm) but more often about ½ of this side free; free portion of hydrotheca (0.31 to 0.56 mm in length) turned outwards to a variable degree so that the aperture may be more or less vertical and parallel to the long axis of the stem or branch, or the aperture may be more oblique: gonotheca somewhat ovoid and compressed, walls strongly and regularly ridged, ridges up to 8 in number, but usually 7 on fully grown gonothecae, discontinuous where they meet in a mesial zig-zag line on the front and back of the gonotheca, each ridge with a free-edged expansion or flounce; distal central aperture raised on a conical structure; fully grown gonothecae up to 1.4 mm in length excluding the pedicel; young gonothecae subspherical when viewed from the broader side, and without the distal conical structure, and with from 3 to 5 ridges. Text-fig. 17.—a–e, Synthecium elegans forma elegans Allman.

Locality: Type locality, New Zealand, lectotype Busk Collection, Brit. Mus. Reg. No 99.7.1.6746; off Cape Maria van Diemen, 35 to 40 fath, as S. ramosum (Totton, 1930); Tamaki and Manakau Harbour, Auckland (C. Trevarthen) 26/5/50, —/8/50, 486, 454; Kawau is., Hauraki Gulf, 5–15 fath. (M. McKenzie) 18/7/56, 465; off Ponui Is., Hauraki Gulf, 10–15 fath. (V.U. Northern Prawn Invest.), 29/8/56, 505; Tauranga, as S. ramosum (Allman, 1885); off Kapiti Is., west coast, North Island, 40 fath. (Capt. Dickinson, “Admiral”), 1/6/56, 479; Cook Strait, 2 stations, 40 to 100 fath. (V.U. Zool. Dept.), February, 1956, 520, 532; Cook Strait, 60–70 fath. (N.Z. Geol. Survey Dept.), 14/8/50, 149; French Pass (Hartlaub, 1901); off Moeraki, 40 fath. (P.M.R.), 11/2/51, 60; Dunedin (Hilgendorf, 1898); E.S.E. Otago Heads, 2 stations, 50–100 fath. (E. J. Batham), 9/1/54, 453, 544; Stewart Island (Coughtrey, 1876). Distribution: New Zealand; Kermadec Islands; Australia; East Indies; Madagascar. As noted above, the greater amount of material in the present collection makes possible a firm decision on the status of S. ramosum Allman and confirms Bale's (1924) opinion and that of others that S. ramosum is a synonym of S. elegans forma elegans Allman. Synthecium longithecum Totton, 1930. Fig. 18, a. (After Totton, Fig. 26.) 1930. Synthecium longithecum Totton, p. 174, Fig. 26. Colony monosiphonic, branched; hydrothecae paired, borne on stem and branches, strongly curved out so that the orifice is nearly vertical, ⅔ of the length being free; free part 0.47 to 0.57 mm in length, adnate part 0.84 to 0.90 mm in length, diameter at orifice 0.25 to 0.26 mm on branches, up to 0.31 mm on some stem hydrothecae; typically two pairs of hydrothecae and a pair of opposite branches per internode: gonotheca, unknown. (Data from Totton, 1930.) Locality: Type locality: off Three Kings Islands, New Zealand, 300 fathoms, and known only from New Zealand. Synthecium tottoni (Totton, 1930). Fig. 18, b (After Totton, Fig. 25, d). Synthecium tottoni nom. nov. for Synthecium robustum Totton, 1930. non Synthecium robustum Nutting, 1904. Text-fig. 18.—a, Synthecium longithecum Totton (after Totton, 1930, Fig. 26). b, Synthecium tottoni Totton (after Totton 1930, Fig. 25d).

Colony monosiphonic up to 5.5 cm in height, branched; hydrothecae paired, borne on stem and branches curving away at an angle of 40° from the axis; ¼ of the adcauline wall free, 0.17 to 0.30 mm in length, fused part 0.57 to 0.92 mm; diameter at orifice 0.20 to 0.26 mm: gonotheca ovoid, compressed at right angles to plane of branching, with from 11 to 12 transverse thickened folds, upturned at the free edge, and apical aperture; 1.45 to 2.0 mm in length, breadth 1.15 to 1.25 mm, thickness 0.70 to 0.80 mm. (Data from Totton, 1930.) Locality: Type locality, off North Cape, New Zealand, 11 to 20 fathoms; and known only from New Zealand. S. tottoni and S. longithecum from northern New Zealand are known to me only from the literature. Both species have very large hydrothecae, a millimetre or more, and up to 1.6 mm in overall length. Some of the material in the present collection of S. elegans forma elegans has hydrothecae of comparable size to those figured for S. tottoni and S. longithecum by Totton. S. elegans forma elegans can be separated from S. tottoni, however, because at least half the hydrotheca is free from the stem, while in S. tottoni only a quarter is free, and because the gonotheca of S. tottoni although very similar in shape and structure to that of S. elegans forma elegans has 3 to 4 more gonothecal ridges than is known for the latter species. S. longithecum has the plane of opening of the hydrotheca parallel to the long axis of the stem, while in S. elegans forma elegans it is variable, sometimes oblique, at others parallel to the axis. It has been shown above that the plane of opening of the hydrotheca is not always a reliable character for distinguishing species of Synthecium, but until more and fertile material of S. longithecum is available, a firm decision on its status cannot be given. Literature Cited Agassiz, L., 1862. Contributions to the Natural History of the United States of America, Vol. iv: 1–372. Boston. —— A., 1865. North American Acalephae. Illus. Cat. Mus. Comp. Zool. Harvard College 11: XIV + 234 pp., 360 text-figs. Cambridge. Alder, J., 1856. A notice of some new genera and species of British Hydroid Zoophytes. Ann. Mag. Nat. Hist. (2), 18: 353–362, Pls. 12–14. Allman, G. J., 1864. On the Construction and Limitation of Genera among the Hydroida. Ann. Mag. Nat. Hist. (May, 1864), ser. 3, Vol. 13: 345–380. —— 1864a. Notes on the Hydroida. Ann. Mag. Nat. Hist. ser. 3, Vol. XIV: 57–64, Pl. ii. —— 1872. A Monograph of the Gymnoblastic or Tubularian Hydroids. Ray Soc. Lond. (Part I, 1871; Part II, 1872). —— 1876. Descriptions of some new species of Hydroida from Kerguelen's Island. Ann. Mag. Nat. Hist. ser. 4, vol. 17: 113–115. —— 1876a. Diagnoses of new genera and species of Hydroida. J. Linn. Soc. Zool. London XII: 251–284, Pls. 9–23. —— 1877. Report on the Hydroida collected during the exploration of the Gulf Stream by L. F. de Pourtales. Mem. Mus. Comp. Zool. Harvard College 5 (2): 1–64, 34 Pls. —— 1885. Description of Australian, Cape and other Hydroida, mostly new, from the collection of Miss H. Gatty. J. Linn. Soc. Zool. London XIX: 132–161, Pls. 7–26. —— 1888. Report on the Hydroida. Part II. The Tubularinae, Corymorphinae, Campanularinae, Sertularinae and Thalamorpha. Rpt. Sci. Res. H.M.S. “Challenger”, Zool. XXIII (LXX) + 90 pp, 39 Pls. Bale, W. M., 1884. Catalogue of the Australian Hydroid Zoophytes. Pub. Australian Museum: 1–192, 19 Pls. —— 1887. The genera of the Plumulariidae, with observations on various Australian Hydroids. Proc. & Trans. Roy. Soc. Victoria, Vol. XXIII: 73–110. —— 1888. On some new and rare Hydroida in the Australian Museum Collection. Proc. Linn. Soc. N. S.W. (2): III: 745–799, Pls. 12–21. —— 1894. Further Notes on Australian Hydroids, with Descriptions of some New Species. Proc. & Trans. Roy. Soc. Vict. (n.s.) VI: 93–117. —— 1913. Further notes on Australian Hydroids. II. Proc. Roy. Soc. Vict. (n s.) XXVI: 114–147, Pls. 12–13. —— 1914. Further Notes on Australian Hydroids. III. Proc. Roy. Soc. Vict (n.s.), XXVII: 72–93, Pls. XI–XIII. —— 1914a. Report on the Hydroida collected in the Great Australian Bight and other Localities. Biol. Res. F. I.S. “Endeavour” 1909–14, Vol. II (1): 1–62, Pls. I–VII.

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