Notocallista and Its Allies.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 68, 1938-39, Page 60

Notocallista and Its Allies. By J. Marwick, N.Z. Geological Survey. [Read before the Wellington Philosophical Society, October, 1936; received by the Editor, December 15, 1937; issued separately, June, 1938.] The affinities of the Venerid genus Notocallista Iredale, 1924, have been questioned by R. B. Stewart (1930, p. 242), who considered the group more closely allied to Pitar than to Paradione, under which the writer (Marwick, 1924, p. 591) had placed it as a subgenus. At the same time, Stewart showed that Paradione had been unnecessarily proposed by Dall as a substitute for Chionella Cossmann, since the earlier Chionella Swainson was clearly a misspelling of Cionella Jeffreys. This criticism has prompted further study of the Australian and New Zealand members of the subfamily Pitarinæ with somewhat unexpected results, the Notocallista, as at present used, being found to consist of three distinct groups. Acknowledgements. For their generous loans and gifts of specimens and for information concerning works not available in Wellington the writer is greatly indebted to the following:—Mrs W. V. Ludbrook, Miss M. K. Mestayer, Dr. R. S. Allan, Mr F. S. Colliver, Mr B. C. Cotton, Dr H. J. Finlay, Mr A. C. Frostick, Mr R. A. Keble, Dr W. R. B. Oliver, Mr A. W. B. Powell, Mr F. A. Singleton, and the Australian Museum. Most of the new Australian species described below had already been noted in manuscript as distinct by Dr Finlay and Mr Singleton. Criteria For Classifying The Pitarinæ. To separate his three chief genera of the Pitarinæ, Callista, Amiantis, and Pitar, Jukes-Browne (1913, p. 337) gave the following criteria as mainly to be relied on: (1) The existence in Amiantis and Pitar of a channel leading from the pit between the anterior laterals of the right valve below the anterior cardinal into the first interdental socket, (2) the position and shape of the left posterior cardinal, (3) the form and direction of the pallial sinus. He further added that neither the characters of the external surface nor the bridge connexion of the anterior and posterior cardinals in the right valve are to be depended upon. Such statements must be interpreted liberally, because small differences in the hinge may be much less significant than great differences in the sculpture. Indeed, the words “small” and “great” are themselves exceedingly loose terms when each is applied to a different character. Consequently, until a mathematical basisis accepted, it may not be possible to arrive at an accurate classification that is acceptable on all sides.

Further, to use any one criterion or set of criteria consistently is extremely difficult. As an example, take Jukes-Browne's (1913, p. 338) treatment of Pitar Römer. Of the genotype V. tumens Gmelin, he stated, “the left posterior cardinal resembles that of Amiantis in being confluent with the nymph along its whole course, and in this respect differs from most other species of Pitaria”; also the pallial sinus is “long, horizontal, linguiform and pointed at the anterior end like that of Amiantis callosa and A. dione.” This suggests that many of the species or groups classed in Pitar by Jukes-Browne and contributing to his conception of the genus may not really belong there. The matter is further complicated by obscurity as to the characters of the genotype itself. H. v. W. Palmer's figure (1926, Pl. 1, fig. 5), reproduced from a photo, shows a deep groove separating the left posterior cardinal for most of its length from the nymph; also Cossmann and Peyrot's (1911, p. 372) line drawing shows a definite groove the full length of the tooth. Certainly in neither of the originals could it have resembled that of Amiantis in being “confluent with the nymph along its whole course.” N. M. Tegland's (1929, Pl. 21) reproductions of Römer's figures show a shell with a very deep escutcheon as also do Cossmann and Peyrot's figures, but the shell of Palmer's photographs has quite a shallow one. Obviously such an important genotype as V. tumens should be definitely fixed to a lectotype or neotype by someone with access to authoritative collections, and carefully detailed figures and descriptions made readily available. Broadly speaking, the hinge is undoubtedly the best guide to Venerid classification, being generally the most conservative part of the shell; nevertheless elements of it vary to a certain extent, even within the one species. As Jukes-Browne noted, the attitude of the left posterior cardinal in the different groups is important. In most of the Cretaceous species which have had their hinges clearly described or figured, e.g., Callistina plana (Sowby.) Europe and India, Aphrodina tippana (Conr.) North America, and Trigonocallista uzambiensis (Woods) South Africa, this tooth is very long and well separated from the nymph. The writer's description and figure (Marwick, 1924, p. 595) of Tikia wilckensi (Woods) New Zealand is wrong. The left hinge has now been further cleared of matrix and shows a long, separated tooth (Pl. 10, fig. 7). Stoliczka's figures present some doubtful cases, but certainly, in the Upper Cretaceous, the dominant hinge had a long and separated left posterior cardinal. In the rich Eocene faunas of the Paris Basin figured by Cossmann and Pissaro there are many species in the subfamily with a free left posterior cardinal, but others such at Calpitaria have it partly fused to the nymph and some such as Microcallista have it fused throughout. In the Miocene, most of the large shells have a fused left posterior cardinal and the position is much as in recent faunas. It seems fair to infer, then, that the free tooth is a primitive characteristic and the confluent tooth has developed from it. This conclusion is supported by the ontogeny of multistriata. Juvenile

shells have the cardinal well separated from the nymph. (See Pl. 10, figs. 1, 2.) The character appears to be connected in some way with the shape of the shell and differs to a certain degree in different individuals within the species. Though, naturally, great differences in the strength of the sculpture exist between different groups and to a less extent within the groups, the kind of sculpture, concentric ridges and grooves tending to obsolesce, is really very constant throughout the subfamily. An important character that has been rather neglected in classification is the manner of setting of the ligament. In some groups, e.g., Notocallista s. str. (Pl. 10, fig. 14), the ligament-walls are quite low and have rounded edges, so that the ligament and the nymphs are well exposed on the closed shell. In others, e.g., Chionella (Pl. 10, fig. 9), the ligament-walls are relatively high, so that the ligament and nymphs are deeply sunk and little exposed on the closed shell. A typical example of this kind of ligament is developed on Lioconcha castrensis (Linné). In some Pitarinæ, although the nymphs are not deeply sunk, the walls are high through being raised as a crest along the dorsal margin (Pl. 10, fig. 3). Dall described this feature in Hysteroconcha, and a less in-curved crest is developed as a specific feature in the Pliocene and Recent New Zealand multistriata. The narrow, low ridge on the posterior inner margin of the Pitarinæ forms a useful datum by which to judge the degree of immersion of the ligament. Most if not all of the criteria of classification show a certain range of variability in the one species, even in specimens from the same locality; for example, the set of the hinge, the shape and size of the sinus, the relative sizes of the teeth, especially the right anterior and the left posterior cardinals; the amount that the right anterior cardinal deflects the groove leading back from the anterior lateral pit, the degree of separation of the pedal retractor from the anterior adductor, and the strength and persistence of the sculpture in the middle of the disc. The Affinities Of Notocallista. Notocallista was introduced by Iredale (1924, p. 210), having the Recent south and east Australian Cytherea kingi Gray as genotype, and in addition containing lamarcki Gray, disrupta Sowerby and the fossil submultistriata Tate. Any discussion as to the affinities of Notocallista must therefore centre on kingi, though obviously close relatives may be highly significant in showing what characters are of systematic importance. N. kingi is fairly large for the family, specimens being commonly 50—60 mm. long. The specimens examined can be divided on their shape into two groups: (1) well inflated, stoutly built, broadly oval shells with relatively high, broad umbones and wide hinge-plate, Twofold Bay, New South Wales, and Port Phillip Bay. Victoria; (2) more longitudinally oval shells, inclined to be lighter built, having relatively lower umbones, a narrower hinge-plate, and therefore shorter cardinal teeth, Tasmania and Gulf of St. Vincent. Each

locality has its own type of colour pattern; curiously, the Tasmanian shells, though near group 2 in shape, have patterns very like those of the Port Phillip Bay shells. Following Iredale's (1924, p. 210) observations at the British Museum, the stout shells of group 1 can be taken as kingi and the more elongate ones of group 2 as subspecies lamarcki Gray. Gray's original description of Cytherea kingi reads: “Shell ovate, heart-shaped, white or pale brown with dark rays, each formed of several narrow lines, the umbones white, 1 inch long, 8/10 inch high.” This description suggests that it was written from juveniles of the Port Phillip Bay kind. The writer's former description of Notocallista (Marwick, 1924, p. 592) was based on specimens of the New Zealand multistriata and parki, together with a specimen of the Tasmanian diemenensis wrongly identified as kingi. It is therefore quite misleading. The surface of the adult kingi is almost smooth, being very irregularly and weakly concentrically striated, even on the juvenile such concentric striae as are developed are irregular. The periostracum on some specimens, e.g., from Twofold Bay, New South Wales, is well developed and has a high glaze, the posterior area in many shells bearing fine radial wrinkles like those of V. chione L. The periostracum of others, however, especially some from southern districts such as Port Phillip Bay is not firmly attached and peels off, leaving the shell with a dull chalky-looking surface very like that underlying the periostracum of V. chione. The hinge of N. kingi appears to the writer to agree in every significant respect with that of V. chione. Take Jukes-Browne's criteria: there is no well-defined channel leading back from the anterior lateral pit; a shallow depression, about normal to the long axis of the pit, leads down to the inter-cardinal socket, the anterior cardinal being undercut to the same small extent in both species; the left posterior cardinal of kingi, as of chione, is relatively short, thin, and closely joined to the nymph. Owing to its broader hinge-plate, the cardinal teeth of kingi (s. str.) are in general relatively longer than those of chione and their set differs (as measured by the more nearly vertical anterior cardinal). That the difference is unimportant is shown by the hinge of subspecies lamarcki, especially of the lightly built Gulf of St. Vincent shells. (See Pl. 11, figs. 2, 3.) The left anterior lateral tooth of both kingi and chione continues up towards the umbo as a definite ridge, simulating a cardinal. The presence of a similar “buttressed” tooth in the West American Oligocene Pitar arnoldi Weaver was the outstanding feature used by N. M. Tegland (1929, pp. 276, 280) to differentiate Katherinella as a new subgenus of Pitar which was said to lack the buttress. Grant and Gale's suggestion (1931, p. 347), that the anterior lateral of the Pitarinæ is really a cardinal tooth moved forward is rather attractive when one considers a hinge like that of Notocallista, in which the tooth in question extends well up under the umbo.

Ontogenetic evidence, however, is against the idea. On young multi-striata and parki of 2 mm. diameter the left anterior lateral is a small, bluntly conic tubercle without any ridge or buttress, apparently originating as an independent growth on the hinge-plate. The buttress develops later and becomes quite prominent (Pl. 10, figs. 1—3). Nor does phylogenetic evidence support the cardinal nature of the anterior lateral. Cretaceous species do not have the tooth buttressed any more than, if as much as, many later species do. The buttress has apparently developed as the anterior margin of the socket into which the right anterior cardinal fits. The pallial sinus of both kingi and chione is obliquely truncated to form a rather sharp point though that of chione is less ascending, and bulges out along its lower boundary to be more nearly equilateral. Finally, in both species the pedal-retractor scar is well separated from that of the anterior adductor. In view of this remarkably close agreement in essential characters, one is tempted to conclude that the two species are quite closely related, differing chiefly in shape, and that Notocallista must take the place, without the seniority of Callista; which is not legally available (Stewart, 1930, p. 239). The position, however, is not so simple, and when the species of the two new groups Striacallista and Fossacallista are considered, the European chione seems with equal if not greater probability to be a remarkably close parallelism to Notocallista. Fossacallista is an Oligocene and Miocene group that lived in Australian and New Zealand seas. Besides having a hinge closely similar to that of Chionella (Pl 10, figs 9, 10), it has a sunken ligament, confluent pedal retractor (Pl 14, fig. 10a), and ascending pallial sinus with a rounded end. The left posterior cardinal is not so well separated from the nymph as that of Chionella, but in some species a well-defined though shallow groove separates them. Fossacallista grades through such species as N. mollesta n.sp. into Striacallista, which has a high ligament, separate pedal retractor (Pl 12, fig. 5a) and truncated sinus; and from Striacallista the change to Notocallista, which also has these characters, is mostly one of increase in size and obsolescence of sculpture. If the parallelism of kingi and chione is an actual fact, then Notocallista must be a recent development from Striacallista for it is not known as a fossil. On the other hand, if chione is really as closely related to kingi as it superficially appears to be, that is, if it is a Notocallista, then the European fossil occurrences take the group back to the Miocene, and the American probably to the Eocene. The geological factor favours solving the problem by parallelism, of which many cases are known in the family. To trace the origin of the European chione, account must be taken of the strongly sculptured Costacallista. The hinges of species of this group are remarkably constant and agree in every respect with that of chione. The groups also agree in size, shape, lunule, ligament, pedal retractor and pallial sinus. Costacallista has been traced back by Palmer to weakly sculptured species in the Eocene [C.

perovata. (Conr.)], so is probably much more closely related to chione than is Chionella, and seems more likely to have given rise to the chione stock through obsolescence of sculpture than does Chionella through evolution of the hinge, ligament, pedal retractor and pallial sinus. On this argument Chionella appears to be off the main line of descent of chione, which, however, remains a parallel development with kingi. Although Macrocallista Meek (monotype V. gigantea Gmelin, Florida) has a smooth outer surface like chione, it differs in its very elongate shape and also in having a bifid left anterior cardinal; moreover the stocks have been distinct throughout the Tertiary. The relationship of Notocallista to Pitar Römer is difficult to determine. As can be seen from Stewart's studies (1930, p. 232) the precise limits of pitar are not easy to define and many of the fossils that have been classed under it are doubtful members. No specimens of the genotype were available in New Zealand for this revision, but specimens of the Aquitanian P. rudis (Philippi) and P. lamarcki (Agassiz) in the Geological Survey Collection seem to possess the essential characters of P. tumens and to be undoubted Pitar s. str. P. nuttalliopsis (Conr.) from the Yorktown Miocene agrees closely with rudis and carries the stock to Eastern U.S.A., where it is strongly represented back to the Eocene (Palmer, 1926). Jukes-Browne (1914, p. 61) in his diagnosis of Pitar (sensu lato) described the pedal retractor as confluent with the adductor and this certainly holds for the three Tertiary species just mentioned. It also holds for the genotypes of the subgenera Capitaria, Pitarina and Agriopoma. In all the specimens examined of Macrocallista, Microcallista, Costacallista, Notocallista s. str. and all the undoubted “Callista” species the pedal retractor is separated from the adductor. If the character, however, be used as a deciding criterion between Pitar and the Macrocallista-Costacallista-Notocallista groups, then Chionella and the new group Fossacallista must go with Pitar. Separation of Chionella from chione causes no trouble, but Fossacallista is quite evidently closely related to Striacallsta and this, with its probable ofshoot Notocallista, must go with the “Callista” groups. The character, therefore, of confluence or separation of the pedal retractor and the anterior adductor cannot be used absolutely, though it certainly is a very useful guide. Conclusions. From the foregoing discussion it can be seen that the exact systematic affinities of Venus chione are uncertain. In almost all its characters it agrees with Notocallista, but there are grounds for believing that this is due to parallelism. V. chione has less in common with Chionella or Macrocallista than with Costacallista (type V. erycina L.), from which it may be an offshoot through obsolescence of the sculpture. Jukes-Browne and Palmer favoured retention of Callista for chione by suspension of the International Rules, but Stewart (1930, p. 239) has pointed out the rather chequered history of the name and its consequent unsuitability.

Perhaps chione will find a home under Megapitaria Grant and Gale as a subgenus of Costacallista. No specimens of the genotype, Cytherea aurantiaca Sowby., were available to the writer for comparison, but Gray's figure of his species, squalidus, which Grant and Gale included in Megapitaria, shows a shell very like chione. Grant and Gale (1931, p. 346) have solved the difficulty of choosing between Macrocallista, Megapitaria, Amiantis, Hysteroconcha and Pitar as genera by suggesting that Pitar, the oldest name, should be taken as a genus and all the other groups with this general type of hinge included as equivalent subgenera. This seems to be the only good alternative to recognising these and such other groups as Chionella, Calipitaria, Tivelina, Costacallista and Notocallista as independent genera. Each course has its advantages; but as our knowledge of the many lineages increases, the tendency will be to elevate all those mentioned and others to generic rank. As noted by Stewart, the use of sectional subdivisions of subgenera is rather clumsy for citation and is not sanctioned by the International Rules; consequently, the best plan seems to be greatly to restrict the older, wide, “Lamarckian” genera and to use genera of intermediate size with only subgeneric divisions. From this point of view, the best classification for chione Linné appears to be under Costacallista (Megapitaria). Australian and New Zealand shells at present classed as Notocallista fall into three main groups which can be treated as subgenera under the genus Notocallista. These subgenera, Notocallista s. str. Striacallista and Fossacallista, typically are easily separable, but their respective limits are difficult to define because of borderline species that combine characters of two groups. Although this is a source of difficulty in drawing up a concise key to the species, it should not act as a barrier to the recognition of systematic groups. The three here recognised are of somewhat unequal value, for Fossacallista is much easier to separate from Notocallista than is Striacallista. According to the evidence so far gained, Fossacallista is probably the oldest group, being related to the European Chionella, which has in its juvenile stage similar fine concentric ridges. Fossacallista lived in Australian and New Zealand seas during the Oligocene and Miocene, but became extinct in both regions before the Pliocene. Striacallista probably developed from Fossacallista in Australia during the Oligocene (N. cudmorei n.sp.), but it did not reach. New Zealand until the Lower Pliocene, when it filled the place formerly occupied by Fossacallista. Notocallista s. str. probably split off from Striacallista in Australia about the Upper Pliocene for the oval variety of the Kalimnan N. submultistriata has much in common. Two other New Zealand Tertiary members of the Pitarinæ are discussed below. Hyphantosoma Dall and Rohea n. gen. Hyphantosoma is a West Indian group with zig-zag sculpture. The New Zealand species, sculpturatus Marshall may have developed this peculiar sculpture independently. Zig-zag colour patterns occur widely in the family and perhaps indicate the common base from which the grooves developed. However, until more definite evidence to the contrary is available, sculpturatus should be classed under Hyphantosoma.

Although the affinities of its hinge are with the European Cretaceous Callista, Rohea could be explained, because of the similar sculpture and ligament as an offshoot from Fossacallista. The sculpture of the whole subfamily, however, is so simple that resemblance in this respect does not carry much weight, therefore the evidence offered by the hinge has been given preference. Stratigraphical Tables. A.—New Zealand. Striacallista. Fossacallista. Costacallista. Hyphantosoma. Rohea. Recent multistriata Pliocene multistriata Upper Miocene makoensis Lower Miocene tersa parki Oligocene parki watti sculpturatus tecta Eocene hectori trigonalis B.—Australia. Notocallista. Striacallista. Fossacallista. Recent kingi diemenensis lamarcki disrupta Pliocene submultistriata Miocene-Oligocene mollesta tatei pestis ancisa lutea opima singletoni cudmorei exigua eburnea Key To Genera And Subgenera Described Below. I. Sculpture of zig-zag grooves. Hyphantosoma II. Sculpture of concentric grooves and ridges.  A. Anterior laterals distant from cardinals, right anterior cardinal long, hinge plate flat. Rohea  B. Anterior laterals close to cardinals, right anterior cardinal short, hinge plate excavated   1. Sculpture strong. Concentric ridges broad and high Costacallista   2. Sculpture weak or obsolete. Concentric ridges low, generally fine.     (a) Pallial sinus rounded, pedal retractor confluent, groove defining left post cardinal well marked, ligament deeply sunk Fosacallista     (b) Pallial sinus truncate, pedal retractor separate, groove defining left post cardinal weak or absent, ligament shallow.       (1) Large shell (adults 40—60 mm. long); periostracum thick, inclined to blister and peel; regular concentrics at extremities of juvenile only, elsewhere weak irregular concentrics; ligament under 1/1 total length of shell Notocallista s. str.

(2) Small shell (adults 12—45 mm. long, many 30 mm.); periostracum thin, closely attached, juveniles with persistent grooves, but always with extremities regularly grooved; ligament ¼ (or over) total length Striacallista Systematic Descriptions. Genus Notocallista Iredale. 1924. Proc. Lin. Soc. N.S.W., vol. 49, p. 182. Genotype (by original designation): Cytherea kingi Gray, Recent, south and east Australia. 1.—Subgenus Notocallista s. str. Notocallista (Notocallista) kingi (Gray). Plate 10, fig. 14; Plate 11, figs. 4, 5, 9. 1827. cytherea kingii Gray, app. to King's Narrative of a Survey of Australia, vol. 2, p. 476. For synonymy see Pritchard and Gatliff, Proc. Roy. Soc. Vic., vol. 16 (n.s.) pt. 1, p. 130. Recent: Twofold Bay, N.S.W.; Port Phillip Bay, Victoria. These and other localities given below are of actual specimens examined, and therefore they are incomplete. Notocallista (Notocallista) kingi subsp. lamarcki (Gray). Plate 11, figs. 1—3. 1838.Cytherea lamarckii Gray, Analyst, vol. 8, p. 308. Recent: North Coast, Tasmania; Gulf of St. Vincent, South Australia. 2.—Subgenus Striacallista nov. Genotype: Cytherea multistriata Sowerby, Recent and Pliocene, New Zealand. Shell rather small, inequilaterally subtrigonal to suboval. Lunule defined by an incised line. Surface shining, bearing fine concentric grooves that tend to obsolesce medially. Hinge like Notocallista, left posterior cardinal confluent with nymph, left anterior lateral but tressed, right anterior and posterior cardinals not bridging. Pedal retractor separated from the anterior adductor. Pallial sinus rather short, ascending, broadly truncate. A.—New Zealand Species. Notocallista (Striacallista) multistriata (Sowerby). Plate 10, figs. 1—3; Plate 12, figs. 1—3. 1851. Cytherea (Callista) multistriata Sowerby, Thes. Conch., vol. 2, p. 628, pl. 136. f. 177. 1913. Macrocallista multistriata Sowby.; Suter, Manual, p. 982, pl. 62, fig. 3a. 1927. Paradione (Notocallista) multistriata (Sowby.); Marwick, Trans. N.Z. Inst., vol. 57, p. 592, figs. 70, 71, 72. Recent: Throughout New Zealand, 5—100 faths. Upper Pliocene: Castlecliff and Kai-iwi, in arenaceous mudstone. Lower Pliocene: G.S. 1609—Timmins Creek, Mangamaire, Mangahao River, 8 miles south-west of Pahiatua. G.S. 2811—Road bridge, Matarua Creek, 5 miles west of Pahiatua. Starborough Creek, Awatere Valley.

Dr R. S. Allan has carefully collected from the many different beds in the Castlecliff—Kai-Iwi section, and his specimens show clearly that the apparent variability of multistriata from this locality has been due to careless collecting. Actually the shells from each bed are remarkably constant in characters and only in two beds, 6 and 10, were two forms collected. Four more or less distinct shapes can be distinguished and the following table shows their distribution. Bed. Trigonal. Elongate-trigonal. Elongate. Oval. No. of valves. 1 blue clays 3 2 shell bed 3 3c shell bed 3 4a sandy blue clays 3 5 blue clays 1 6 egenum sands egenum sands 6, 4 7 shell bed 10 blue clays blue clays 1, 1 11 shell bed 6 13 fossilif. blue clay 6 15 blue clays 2 18 gritty shell bed 1 20 fossilif. grits 1 22 cement stone band 1 From this it can be seen that the oval shell occurs fairly consistently in the shell beds and coarse bands, while the others occur mostly in fine muddy beds. Most Recent specimens seen (Awanui Bay, Great Barrier Island and Foveaux Strait) belong to the trigonal form, the northern shells differing from the southern only in having a bright, well-defined colour pattern. Shells in the Auckland Museum from mud, Cook Strait, 2½ miles north-west from Waikanae, are of highly elongate shape and agree very closely indeed with those from beds 1 and 5. Those classed as elongatetrigonal are intermediate in shape between typical trigonal and elongate forms. It may be that these differences in shape are directly due to the environment, but this does not explain the absence of the oval form from Recent faunules. Lower Pliocene shells from near Pahiatua seem to combine the characters of the oval and the trigonal forms, so it may be that we have here the emergence of a new species. In bed 6 at Castlecliff, the egenum sands, the elongatetrigonal and the oval forms both occur without grading, thus tending to confirm the indications that the two forms are distinct. Shell beds are liable to contain forms from different faunules, for many of them must be concentrations of mullusca brought about by the removal of the sands in which they were buried by increase in the rate of bottom currents; but the egenum sands do not appear to be of this nature. A specimen in the Geological Survey collection from Star borough Creek is strongly subtrigonal, having broad, high beaks, a

narrow posterior end and a greatly inflated shell. In shape it resembles the subtrigonal form of the Australian Lower Pliocene N. submultistriata though its escutcheon is not so flat. Among the Pahiatua shells mentioned as showing a gradation from oval to trigonal are some strongly subtrigonal, thus approaching the Star-borough Creek shell. Further collecting, however, is necessary before the systematic recognition of this form could be justified. The oval form Castlecliff is so distinct that it is here recognised as a separate subspecies. Notocallista (Striacallista) multistriata ovalina n. subsp. Plate 12, figs. 4, 5, 5a. Shell distinguished from multistriata by its oval instead of subtrigonal form, most apparent in its broadly convex posterior end. The hinge shows no consistent differences, but the sculpture of fine regular ridges persists across the disk, while that of multistriata is obsolete medially, the ridges becoming weak and highly irregular. The dorsal crest in the left valve is often raised particularly high. Holotype in Canterbury Museum. Length, 29.5 mm.; height, 22.4 mm.; inflation (1 valve), 7.5 mm. Upper Pliocene: Beds 2, 3c (type), 4a, 6, 7, Castlecliff; beds 11, 18, Kai-Iwi (R. S. Allan coll.). For a discussion on this subspecies see under multistriata. B.—Australian Species. Notocallista (Striacallista) diemenensis (Hanley). Plate 12, figs. 6—8. 1844. Cytherea dimenensis Hanley, P.Z.S., pt. 12, p. 110. 1903. Meretrix planatella Lamk., Pritchard and Gatliff, P.Z.S. Vic., vol. 16 (n.s.), p. 129. (Not of Lamk.) Recent: Tasmania; Western Port, Victoria, 8 faths. (C. J. Gabriel); Gulf of St. Vincent, South Australia. By examining the types, Hedley (1913, p. 270) has shown that the earlier planatella Lamarck, thought by some to be synonymous with diemenensis (Smith, Challenger, XIII, p. 136) really is a young Costacallista from north-west Australia. The sculpture of diemenensis is coarser than that of multistriata and the ligament has much lower walls. Notocallista (Striacallista) disrupta (Sowerby). Plate 12, figs. 12, 14, 15. 1853. Cytherea disrupta Sowby., Thes. Conch., vol. 2, p. 743, pl. 163, f. 208, 209. 1885. Cytherea (Callista) disrupta Sowby., Smith, Challenger, vol. 13, p. 135, pl. 1, f. 4—4e. Recent: Specimens seen came from Sydney Harbour and from Calloundra, Queensland, the latter considerably less elongated. Iredale (1924, p. 210) recorded typical disrupta from Twofold Bay and noted that “Tasmanian shells named disrupta varied a little further while Sydney shells referred to this species should have a distinctive name”. Later (1929, p. 338) he advocated the use

of laevigata Sowerby for the Sydney and Calloundra shells. In describing his Venus laevigata (Thes. Conch., vol. 2, p. 103) Sowerby gave three figures, 156, 157, and 158. Figure 156 represents the exterior of a left valve 27 mm. × 19 mm. with a long, straight, relatively high posterior dorsal margin and a straight, steep, anterior dorsal margin. In shape it is thus not at all like the Sydney shells allotted to N. disrupta which have a strongly convex posterior dorsal margin and a strongly concave anterior dorsal margin. The colour pattern of Sowerby's figure 156, namely, rays formed of black zig-zags on a yellowish ground, is not that of Notocallista but of Eumarcia nitida (Q. and G.), which, moreover, has a high, straight dorsal margin, though, to be sure, the anterior end projects more. Sowerby's figures 157 and 158 are of a left valve measuring 39 mm. × 25 mm. They show a hinge with three equally diverging cardinal teeth and no trace of an anterior lateral, exactly, indeed, as in Eumarcia nitida and quite unlike Notocallista. Moreover, the interior colour, a pale salmon band along the pallial line and filling the sinus, added to the hinge evidence, leaves no doubt whatever that the shell is a Eumarcia. Accordingly, laevigata is not available for any groups of Notocallista. It seems possible that a form of the southern diemenensis has been identified by authors as disrupta. Thus Iredale mentioned “disrupta from Tasmania,” yet May in his Check List recorded only kingi and diemenensis (as Macrocallista). Also Pritchard and Gatliff in their Catalogue of the Marine Shells of Victoria recorded Meretrix disrupta from Port Phillips Heads, with the remark: “We agree with Mr. Hedley in regarding this as distinct from planatella (= diemenensis), though very closely related.” Now Sowerby's figure 20 of disrupta shows a shell 47 mm. × 35 mm. which he described as “laevigata … concentrice tenuiter striata … lunula excavata,” emphasising in his notes the excavated lunule. Calloundra shells agree in size, shape, and excavated lunule, and the Sydney shells differ from these only in being more elongate, though both have a much less conspicuous colour pattern than Sowerby's figure. N. diemenensis, on the other hand, measures about 32 mm × 24 mm., often much less, is concentrically ridged and has an almost straight lunular margin. It is unlikely that there would be any hesitation such as suggested by Pritchard and Gatliff about separating shells like the Calloundra and Sydney ones from diemenensis. Moreover, the southern shells lack the several deep growth-furrows that so characterize Sydney and Queensland ones. However, the sorting out of the true disrupta and its regional relatives cannot be carried out with the material available in New Zealand. All that can be done in this paper is to remove the Calloundra and Sydney shells from laevigata and provisionally place them back under disrupta. It is suggested that the true disrupta is a brightly patterned shell having the form of the Calloundra ones, but being somewhat less inflated. The Sydney ones, being consistently more elongate, represent a distinct subspecies. For careful copies of Sowerby's figures of disrupta and laevigata I am indebted, through the kind agency of Mr. F. S. Colliver, to Mr. A. C. Frostick of Melbourne.

Notocallista (Striacallista) submultistriata (Tate). Plate 12, figs. 9—11, 13. 1887.Cytherea submultistriata Tate, Trans. Roy. Soc. Sth. Aust., vol. 9, p. 160, pl. 18, figs. 6, 8. 1924. Notocallista submultisriata (Tate); Iredale, Proc. Lin. Soc. N.S.W., vol. 49, p. 210. Pliocene (Kalimnan): Upper beds Muddy Creek (type). Jimmy's Point (F. A. Singleton). Forsyth's Grange Burn. Kalimna. Two different shapes are common in this species, one a fairly regularly inflated form with erect umbones, the other, generally smaller, is more inflated, has a flattened escutcheon bounded by a rounded ridge, more forward-curved umbones and a narrower posterior end, making the outline more subtrigonal. Both forms were figured by Tate, and of the eight specimens examined during the present revision six belong to the second subtrigonal variety. Whether the differences merit systematic recognition should not be decided without examining the field occurrences of a large number of specimens. From the Recent disrupta the Pliocene multistriata is readily distinguished by its different shape, being always relatively shorter in front and having a much less excavated lunule. Further, the left posterior cardinal ofsubmultistriata is considerably longer and stronger than that of disrupta. However, submultistrata appears undoubtedly to be directly ancestral to the Recent shell. Notocallista (Striacallista) lutea n.sp. Plate 13, figs. 5, 6. Shell small, moderately inflated, thin, elongate, beaks not very prominent. Surface shining, with very fine concentric grooves, many persisting across the disk. Left posterior cardinal joined to the nymph without a separating groove. Hinge-plate lightly built. Ligament not deeply set, the walls low, the posterior dorsal marginal ridge meeting them at about half height. Pedal retractor separated from the adductor by a very short line. Pallial sinus ascending, roundly truncated. Holotype in Auckland Museum (ex Finlay collection). Length, 13.8 mm.; height, 10 mm; inflation (1 valve), 3.5 mm. Oligocene-Miocene: Lower beds (Balcombian) Muddy Creek, Vic. This shell has been indentified as N. eburnea (Tate), which it resembles in size and general appearance. It can readily be separated, however, by its shallow ligament and more elongate shape. It further-differs from eburnea in the narrower, subtruncate sinus, separated pedal retractor, more persistent and finer sculpture and less inflation. The differences are more accentuated in juveniles, especially because of the marked inflation of eburnea. Notocallista (Striacallista) cudmorei n.sp. Plate 13. figs. 1, 2. Shell rather small elongate oval, beaks inconspicuous. Sculpture of fine concentric grooves, 6 to 8 per mm., becoming weak and irregular and some obsolete medially. Hinge very like that of

multistriata, except that the right posterior cardinal is longer and narrower. The ligament is set at about the same depth as in multistriata but the walls are slightly lower, not being raised in a dorsal crest. The sinus also is truncated and similar in shape to that of multistriata. The pedal retractor is separated from the adductor. Holotype presented to National Museum, Melbourne, by Mr. F. A. Cudmore. Length, 19 mm.; height, 12.5 mm.; inflation (1 valve), 4 mm. Oligocene-Miocene: Lower beds, Table Cape, Tasmania. N. cudmorei presents an extraordinary likeness to the New Zealand Recent and Pliocene multistriata. It can be distinguished by the low ligamental walls not forming a dorsal crest and by the less-conspicuous beaks, but the differences are relatively small and individual variations might cause difficulty in identifying a given specimen. There can be little doubt that N. cudmorei is an early member of the stock that colonised New Zealand from Australia about the late Miocene or early Pliocene. Notocallista (Striacallista) mollesta n.sp. Plate 13. figs. 7–9. Shell of average size for the subgenus, suboval, beaks low. Sculpture of fine, regular, concentric grooves and bevelled ridges 4 to 5 mm. persisting across the disk. Ligament well sunk with high walls. Hinge teeth like those of multistriata except that the left posterior cardinal of the holotype is more separated from the nymph. Pedal retractor separated from the adductor. Pallial sinus ascending, roundly truncated. Holotype in collection of N.Z. Geological Survey. Length, 26.5 mm.; height, 19.5 mm.; inflation (1 valve), 6.5 mm. Locality: 400–500 ft., Abattoirs bore, Adelaide. Age uncertain. The deep-set ligament and well-defined left posterior cardinal indicate classification under Fossacallista, but the sinus is inequilateral and shows traces of truncation, and the pedal retractor is not confluent with the adductor. The persistent sculpture is reminiscent of some early Fossacallista, but one of the specimens has a medial patch of obsolescent sculpture. Therefore the well-defined adult ridges may be an anagenetic feature derived from a sub-smooth stage. N. mollesta is not clearly separable from the next species N. pestis, under which the matter is further discussed. Notocallista (Striacallista) pestis n.sp. Plate 13, figs. 3, 4. Shell about average size for the subgenus, suboval to subtrigonal, narrowed posteriorly, beaks moderately conspicuous, rather narrow. Surface shining, posterior and anterior parts bearing concentric grooves and ridges, about 4 per mm., but these are very irregular and die out over the middle of the disk. Ligament shallow, its walls low. Hinge close to that of multistriata. Pedal retractor close to the adductor but separated from it. Pallial sinus roundly truncate.

Holotype in Auckland Museum (ex Finlay Collection). Length, 27 mm.; height, 19 mm.; inflation (1 valve), 5.5 mm. Locality: 400–500 ft., Abattoirs bore, Adelaide. Age uncertain. Although the holotypes of N. pestis and N. molesta, which come from the same locality, are, on the criteria used in this paper, almost, if not quite, subgenerically separable, paratypes seem to show a gradation between the two species. Of the 9 specimens examined from the Abattoirs bore no clear-cut groups could be formed. The only two characteristic specimens of N. mollesta have a sunken ligament and persistent sculpture. They also have a fairly regularly oval outline. The other specimens have persistent sculpture and an oval shape, but they have a shallow ligament and so have been classed under pestis. The other five specimens with shallow ligaments and obsolescing sculpture differ considerably among themselves in shape, in the pallial sinus, in the degree of separation of the pedal retractor from the adductor, and of the left posterior cardinal from the nymph. The deep ligament and separated left posterior cardinal of the type of N. mollesta are characters of Fossacallista, but the pedal retractor is not confluent and the pallial sinus is roundly truncate. Thus as well as showing mixing of specific characters, the Abattoirs bore collection shows blending of the sub-genera Fossacallista and Notocallista. The most convenient refuge at present is to explain the mixture as due to hybridisation of stocks, but it is somewhat disturbing to find characters that apparently have generic (or subgeneric) significance in the rest of the family, yet that cannot show consistent specific divisions in this small group. The specimens were obtained from some 100 ft. or so of beds in a bore, and probably more than one horizon is represented (N. H. Woods, 1931, p. 147), but this does not explain away all the anomalies. N. pestis agrees closely with multistriata in shape, sculpture, and hinge, the most consistent difference being the more sharply truncate sinus of multistriata. 3.—Subgenus Fossacallista nov. Genotype: Paradione (Notocallista) parki Marwick. Awamoan (Low. Miocene), New Zealand. Shell rather small, suboval. Lunule defined by an incised line. Surface shining, finely concentrically grooved, tending to be smooth medially. Hinge like Notocallista, but the left posterior cardinal tends to be less closely welded to the nymph, some specimens showing a well-defined groove between the two. Ligament deeply sunk with high walls which, however, are scarcely raised above the well-marked posterior marginal ridge. Pedal retractor confluent with the anterior adductor. Pallial sinus moderate, ascending, rounded at the end. Readily distinguished from Notocallista and Striacallista by the sunken ligament, confluent pedal retractor, and rounded pallial sinus. In these characters it agrees with Chionella, and relationship to this group is further indicated by the shallow groove that in some specimens separates the left posterior cardinal from the nymph. Thus

Fossacallista, if considered by itself, could well be classed under Chionella, but gradation towards Striacallista and thence to Notocallista suggests that this persistent southern stock should be recognised as a separate generic group under the oldest name, Notocallista. A.—New Zealand Species. Notocallista (Fossacallista) tecta n.sp. Plate 14, figs. 5, 6. Shell small, more elongate-oval than parki and having very fine regular grooves about 8 per mm. persisting over the whole disk. The lunule is more excavated than that of parki, so that its dorsal margin is noticeably more concave, in the manner of N. disrupta. The pallial sinus does not reach the middle, tapers, ascends and is rounded at the end. Holotype in Auckland Museum (ex Finlay Collection). Length, 17.5 mm.; height, 12 mm.; inflation (1 valve), 4 mm. Oligocene: Chatton (type). G.S. 1897—Wendon. G.S. 1821—Wharekuri greensand. Notocallista (Fossacallista) watti n.sp. Plate 14, figs. 12, 13. Shell considerably larger than parki, umbones wide, prominent. Surface shining and nearly smooth, very fine concentric grooves 5 to 6 per mm. distally, becoming obsolete and further apart medially. Young shells of the same size as parki are more elongate, but the adults have a similar shape, being distinguished chiefly by their smoother surface. Holotype in Collection of N.Z. Geological Survey. Length, 32 mm.; height, 25.3 mm.; inflation (1 valve), 9 mm. Oligocene: G.S. 1473—Upper part of limestone, Trig Z, Otiake. This species is named in honour of the late John Watt, my first companion in the Otiake district. Notocallista (Fossacallista) parki (Marwick). Plate 10, fig. 10; Plate 14, figs. 8, 9, 10, 10a. 1926. Paradione (Notocallista) parki Marw., Trans. N.Z. Inst., vol. 57, p. 593, figs. 66–69. Upper Oligocene: Clifden band 6a;? Clifden, east side, C; Target Gully glauconitic sandstone; sandstone, All Day Bay; Parson's Creek, Oamaru (type). The grooves are generally 4 to 5 per mm. and so somewhat coarser than those of watti and noticeably more so than those of tecta. Notocallista (Fossacallista) tersa n.sp. Plate 14, figs. 4, 7. Shell rather small, more elongate oval than parki and nearer the shape of tecta, from which it differs in being more acuminate posteriorly. Sculpture of fine concentric grooves about the strength of tecta but very irregular, obsolete medially. Lunular margin slightly concave, intermediate between tecta and parki. Hinge with a very small right posterior cardinal and with the left posterior cardinal coalescing with the nymph. Pedal retractor confluent with the adductor, the junction somewhat restricted. Pallial sinus roundly truncated.

Holotype in Auckland Museum (ex Finlay Collection). Length, 20 mm.; height, 13 mm.; inflation (1 valve), 4.8 mm. Locality: Shell bed, Target Gully, Oamaru. A single specimen 29 mm. long in the Geological Survey Collection, from Target Gully, has coarse sculpture and rather straight lunular margin like parki, but the long shape of tersa and tecta. Its pallial sinus is rounded in front. Judged by its colour it probably came from the glauconitic sandstone underlying the shell-bed. N. parki occurs in this bed and the specimen may represent a transition or a hybrid between parki and tersa, with which it can be classed because of its shape. Notocallista (Fossacallista) makoensis (Marwick). Plate 13. fig. 12. 1931. Paradione (Notocallista) makoensis Marw., N.Z. Geol. Surv. Pal. Bull., 13, p. 78, figs. 99, 100. Upper Miocene (Taranakian): 1324, Waikohu Survey Dist. 1350, Bruce Ridge Road, Tokomaru Survey Dist. 2313, Ngahape Stream, Motuotaraia Survey Dist. The interior characters of this species have not yet been determined, so its position in Fossacallista is uncertain. However, the general probabalities seem to indicate a degenerate representative at the end of the Fossacallista reign rather than the first representative of the Australian Striacallista stock in New Zealand. B.—Australian Species. Notocallista (Fossacallista) eburnea (Tate). Plate 13, figs. 16–18. 1887. Cytherea eburnea Tate, Trans. R.S. Sth. Aust., vol. 9, p. 160. pl. 18, fig. 7. Shell small, fairly well inflated, having a high, arched posterior dorsal margin. Surface smooth and shining, sculpture obsolete over most of the disk but regular concentric grooves on the juvenile and irregular weak ones distally on the adult. Left posterior cardinal well developed though narrow, tending to be bounded along its upper side by a groove. Hinge-plate lightly built, so that the left anterior lateral is slender and set in a hollow. Right anterior lateral pit with an extremely shallow groove leading to the cardinal socket. Ligament deeply sunk, with high walls, posterior dorsal marginal ridge well defined. Pedal retractor confluent, pallial sinus relatively short and very broad, rounded at the end. Oligocene-Miocene: River Murray Cliffs below Morgan (Janjukian). Notocallista (Fossacallista) opima n.sp. Plate 13, figs. 13–15. Shell small, greatly inflated, beaks broad and prominent. Surface shining, with a few irregular grooves persisting across it from the distal parts, where they are well spaced and fairly regular. Hinge-plate narrow, left posterior lateral bounded dorsally by a groove. Left anterior lateral relatively slender, sharply pointed.

Right anterior lateral pit small, median cardinal low down on the hinge. Ligament deeply sunk. Pedal retractor confluent. Pallial sinus ascending, very wide, tapering rapidly, broadly rounded at the end. Holotype in Melbourne National Museum Collection. Length, 13.3 mm.; height, 11.2 mm.; inflation (1 valve), 4.4 mm. Oligocene-Miocene: Balcombe Bay, Victoria (Balcombian). N. opima is easily distinguished from eburnea by its much greater inflation, more oval outline and broader, more prominent beaks. The sculpture is not so obsolete as that of eburnea and the lunule is relatively shorter and broader. Internally the species agree well, so they must be closely related. Notocallista (Fossacallista) exigua n.sp. Plate 13, figs. 10, 11. Shell small, oval, much inflated, beaks not very prominent. Surface shining, with fine, regular, closely-set grooves becoming somewhat obsolete medially. Hinge like that of opima, except that the ligament is not quite so deeply set. Pallial sinus as in opima. Holotype in Auckland Museum (ex Finlay Collection). Length, 8.6 mm.; height, 6.2 mm.; inflation (1 valve), 2.5 mm. Oligocene-Miocene: Aldinga (Janjukian). This species differs from young opima of the same size in its more oval outline and less prominent beaks. The sculpture is much finer and more persistent than that of opima. Notocallista (Fossacallista) tatei (Cossmann). Plate 14. figs. 1–3. 1887. Cytherea tenuis Tate, Trans. R.S. Sth. Aust., vol. 9, p. 159, pl. 14, f. 16. 1920. Callista Tatei Cossmann, Rev. crit. de Paléozool., vol. 24, p. 37, not Cytherea tenuis Hall and Meek, 1854. The surface is smooth and shining over much of the disk, traversed by extremely fine, slightly irregular lines. The sculpture of concentric grooves about 6 per mm. is developed only for a short distance along the dorsal margin and near the lunule. In the left hinge the posterior cardinal is long and fairly strong, being faintly defined from the nymph, and the anterior lateral is high, slender and buttressed. In the right hinge the posterior cardinal is of moderate size, and the anterior lateral pit leads indirectly to the cardinal socket and a slightly undercut anterior cardinal. The ligament walls are only moderately high, and the ligament itself not very deeply sunk with reference to the left posterior marginal ridge. The pedal retractor is confluent with the anterior adductor, but the junction is somewhat constricted. The pallial sinus is broad at its mouth and rounded at the end with just a suggestion of truncation. Oligocene-Miocene: Bird Rock Cliffs, Torquay (= Spring Creek), Victoria (F. A. Cudmore Collection). Notocallista (Fossacallista) ancisa n.sp. Plate 14, figs. 11, 14. Shell rather small, fragile, suboval; beaks rather prominent. Sculpture of fine concentric grooves 5 to 6 per mm. persisting across

the polished disk, but slightly irregular medially. Ligament deeply sunk below the right posterior marginal groove. Pedal retractor confluent. Pallial sinus with a wide mouth and a rounded end. Holotype in Cudmore Collection. Length, 21.6 mm.; height, 16.8 mm.; inflation (1 valve), 6 mm. Oligocene-Miocene: Grice's Creek, Frankston, Victoria (Balcombian). This species is closely related to tatei (= tenuis) but differs in having persistent concentric sculpture, more deeply sunk ligament, and straighter, more steeply inclined lunular margin. In general appearance N. ancisa strongly resembles the New Zealand N. watti, differing only in having persistent sculpture across the disk. Notocallista (Fossacallista) singletoni n.sp. Plate 14, figs. 15, 16. Shell of moderate size, strongly built, broadly suboval; beaks broad and prominent, a faint radial depression traversing the posterior area. Sculpture of well-marked, persistent grooves, about 4 per mm., separating low, bevelled ridges. In hinge and other internal characters like cudmorei. The lunule is double, but the inner groove is somewhat irregular and probably had a pathological origin. Holotype in Auckland Museum (ex Finlay Collection). Length, 26 mm.; height, 21 mm.; inflation (1 valve), 7 mm. Oligocene-Miocene: Table Cape (Janjukian). Mr Singleton, who has seen the holotype, says that it is almost certainly from the upper beds. N. singletoni is distinguished from N. ancisa and N. tatei by its higher, more prominent beaks, its greater relative height, and its coarser, persistent sculpture. The ligament is perhaps slightly shallower than in ancisa, also the pallial sinus is a shade narrower, but these differences are probably not important. This species is dedicated to Mr F. A. Singleton, Melbourne University, who supplied much of the Australian fossil material for this study, also helpful notes on the different specimens. Genus Costacallista Palmer. 1926. Pal. Amer., vol. 1, no. 5, pp. 73, 84. Type (by orginal designation): Venus erycina Linné, Recent, Indo-Pacific. Figured: Palmer, op. cit., Pl. 15, figs. 17, 18, 21. Costacallista hectori (Finlay and Marwick). Plate 10, figs. 13, 15. 1937. Notocallista hectori Fin. and Marw., N.Z. Geol. Surv. Pal. Bull., 15, p. 101, pl. 14, figs. 11, 12, 16. When described, this species was compared with the Parisian Eocene Tivelina elegans (Lamk.) and T. baudoni Cossman. These, together with T. elegantula (Desh.) and distans (Desh.), can well be classed as Costacallista, and hectori, having similar sculpture, may be included. Certainly the broad, concentric ridges of hectori separate it from any of the groups of Notocallista yet known.

Typical Tivelina (G.-type, Cytherea tellinaria Lamk.) is sub-triangular with a smaller pallial sinus and without strong sculpture. Jukes-Brown (1913, p. 342) has pointed out that Cossmann's Tivelina of the Iconographie Complète contains several different groups, among which he used Callista for baudoni, elegans and elegantula. The species heberti (Desh.) from the Cotentin Eocene is also strongly ridged and, like the other species mentioned, appears to differ from the type of Costacallista only in its small size. Genus Pitar Römer. 1857. Krit Untersuch. d Art. d. Moll., Venus, p. 15. Type (by monotypy): Venus tumens Gmelin, Recent, West Africa. For reference to figure see above. Subgenus Hyphantosoma Dall. 1902. Proc. U.S. Nat. Mus., vol. 26, p. 354. Type (by original designation): Cytherea carbasea Guppy, Miocene, Jamaica. Figured: Woodring, Miocene Moll. Bowden, Pelecypods. and Scaphopods, Pl. 20, figs. 15–19. Pitar (Hyphantosoma) sculpturatus (Marshall). Plate 10, fig. 8, 11 1918. Macrocallista sculpturata Marshall, Trans. N.Z. Inst., vol. 50, p. 272, pl. 21, figs, 6, a. 1927. Pitar (Hyphantosoma) sculpturatus (Marsh.); Marwick, Trans. N.Z. Inst., vol. 57, p. 594, figs. 74–76. ? Miocene: G.S. loc. 800, west slope of Puketoi Range opposite Ormondville. Oligocene: Pakaurangi Point (Hutchinsonian). The left hinge has not yet been seen, the four specimens known from Pakaurangi Point being right valves and the single one from loc. 800 a closed individual. The New Zealand species differs from the genotype, carbaseus, in having a somewhat wider right posterior cardinal and a longer groove leading to the anterior lateral pit, which is thus more distant from the cardinals. The ornamentation of sculpturatus is considerably weaker than that of carbaseus, being intermediate between this species and opisthogrammatus Dall. These differences, however, do not appear to have more than specific value, especially in view of the close agreement of the other characters, even to the confluence of the pedal retractor. No satisfactory explanation has yet been put forward as to how this peculiarly sculptured West Indian group came to inhabit New Zealand seas during the Oligocene-Miocene, and the possibility of sculpturatus being a parallel development from the Fossacallista stock must be considered. No likely ancestors are known in New Zealand, but the greatly inflated N. opima from the Balcombian of Victoria, though smaller, has a similar shape and hinge. Its lateral pit, however, is close to the cardinals and, of course, it shows no trace of zig-zag sculpture. Consequently it presents no positive evidence that sculpturatus arose from this kind of shell.

Possibly the left valve of sculpturatus, when found, will supply additional evidence of origin. The left posterior cardinal of carbaseus is quite separate from the nymph and diverges noticeably from it with age. Corresponding to this, in the right valve, the posterior cardinal is narrow and more than its own width distant from the nymph. On the other hand, the right posterior cardinal of sculpturatus is relatively broad, and the space between it and the nymph is narrow. This suggests that the left posterior cardinal of sculpturatus is closely connected with the nymph and favours derivation from the Fossacallista stock. The right anterior hinge-plate of carbaseus is more excavated than that of sculpturatus and the lateral teeth are weaker; but, admittedly, the differences are not great, and it seems advisable to regard sculpturatus as a true Hyphantosoma until a definite case to the contrary is established. In this connexion it should be remembered that New Zealand has a few other faunal contacts with the southern part of North America. Curiously enough, two outstanding examples are also Veneridæ, namely, Chione str. and Protothaca, to which stocks the New Zealand groups Austrovenus and Tuangia are closely related, neither being represented in Australia or the Old World. Genus Rohea nov. Genotype: Paradione (Notocallista) trigonalis Marwick, Oligocene, New Zealand. Shell rather small, suboval, with somewhat narrow, erect, prominent beaks. Surface shining, bearing fine concentric grooves which become irregular and obsolete medially. Hinge-plate broad, flat and solid anteriorly, right hinge with two long anterior cardinals, the anterior slightly stronger, posterior cardinal very short and narrow, bifid; anterior lateral pit distant from the cardinals by its own length and not connected with the anterior cardinal socket by any groove. The lateral teeth are short and raised to a sharp point. Left posterior cardinal separated from the nymph by a groove, anterior lateral not buttressed and with a deep pit ventrally. Ligament well sunk, with high walls. Pedal retractor separated from the adductor. Pallial sinus slightly ascending, tapering, roundly truncated. The sunken ligament resembles that of Fossacallista and Chionella, but the arrangement of the teeth differs greatly, both from these as well as from any of the Notocallista, Costacallista, or Pitar groups. The long, straight, right anterior cardinals, distant anterior lateral, and unexcavated hinge-plate recall such genera as Aphrodina and Callistina, Dosiniopsis and Marwickia, but there are no posterior laterals as in the last two. The long left posterior cardinal, well separated from the nymph, agrees with Aphrodina and Callistina, and the right posterior cardinal is short and slender as in Callistina. Accordingly, if the hinge is to be taken as a guide, Rohea must be a descendant of the European Cretaceous stock typified by C. plana (Sowby.). The New Zealand Cretaceous Tikia Marw. has a short right anterior cardinal and the hinge-plate anteriorly is well excavated, the right lateral pit communicating with the anterior cardinal socket.

Fig. 1.—Notocallista (Striacallista) multistriata (Sowby.), juvenile, 2 mm. long, × 25. Fig. 2.—Ditto, 3 mm. long, × 20. Note larger anterior lateral. Fig. 3.—Ditto, 5.5 mm. long, × 12. Anterior lateral buttressed. Figs. 4–6.—Rohea trigonalis (Marw.), n.gen., topotypes, × 1¼. Fig. 7.—Tikia wilckensi (Woods), Upper Cretac., Amuri Bluff, × 1. Figs. 8, 11.—Pitar (Hyphantosoma) sculpturatus (Marsh.), topotype, × 1½. Fig. 9—Chionella ovalina (Desh.), Paris Basin, × 3. Fig. 10.—Notocallista (Fossacallista) parki (Marw.), holotype, × 3. Fig. 12.—Costacallista (Megapitaria) chione (Linné), Malta, × 1. Figs. 13, 15.—Costacallista hectori (Fin. and Marw.), paratype and holotype, × 3. Fig. 14.—Notocallista kingi (Gray), Twofold Bay, N.S.W., × 2½.

Figs. 1–3.—Notocallista kingi lamarcki (Gray), Gulf of St. Vincent, × 1. Figs. 4, 5, 9.—Notocallista kingi (Gray), Twofold Bay, N.S.W., × 1. Figs. 6, 7, 8.—Costacallista (Megapitaria) chione (Linné), Malta, × 1.

Figs. 1–3.—Notocallista (Striacallista) multistriata (Sowby.), Stewart Is., × 1. Figs. 4–5.—Notocallista (Striacallista) multistriata ovalina n.subsp., holotype, × 1. Fig. 5a.—N. multistriata ovalina n.subsp. Separate muscle scars of pedal retractor and anterior adductor. Figs. 6–8.—Notocallista (Striacallista) diemenensis (Hanley), Tasmania. × 1. Fig. 9.—Notocallista (Striacallista) submultistriata (Tate), McDonald's Muddy Creek, × 1. Figs. 10, 11.—Ditto, Jimmy's Pt., Kalimna, × 1. Fig. 13.—Ditto, Jimmy's Pt., subtrigonal form, × 1. Figs. 12, 14, 15.—Notocallista (Striacallista) disrupta (Sowby.), Sydney Hbr., × 1.

Figs. 1, 2.—Notocallista (Striacallista) cudmorei n.sp., holotype, × 1½. Figs. 3, 4.—Notocallista (Striacallista) pestis n.sp., holotype, × 1. Figs. 5, 6.—Notocallista (Striacallista) lutea n.sp., holotype, × 2. Figs. 7–9.—Notocallista (Striacallista) mollesta n.sp., paratype and holotype, × 1. Figs. 10, 11.—Notocallista (Fossacallista) exigua n.sp., holotype, × 3. Fig. 12.—Notocallista (Fossacallista) makoensis (Marw.), Ngahape Stm., × 2½. Fig. 13.—Notocallista (Fossacallista) opima n.sp., paratype. × 3. Figs. 14, 15.—Notocallista (Fossacallista) opima n.sp., holotype, × 2. Figs. 16–18.—Notocallista (Fossacallista) eburnea (Tate), topotypes, × 2.

Figs. 1–3.—Notocallista (Fossacallista) tatei (Cossmann). Torqua. × 1. Figs. 4, 7.—Notocallista (Fossacallista) tersa n.sp., holotype, × 1½. Figs. 5, 6.—Notocallista (Fossacallista) tecta n.sp., holotype, × 1½. Fig. 8.—Notocallista (Fossacallista) parki (Marw.), All Day Bay, × 1 3/5. Figs. 9, 10.—Notocallista (Fossacallista) parki (Marw.), holotype. × 1 3/5. Fig. 10a.—N. parki (Marw.). Confluent muscle scars of pedal retractor and anterior adductor, × 5. Figs. 11, 14.—Notocallista (Fossacallista) ancisa n.sp., holotype, × 1½. Figs. 12, 13.—Notocallista (Fossacallista) watti n.sp., holotype, × 1. Figs. 15, 16—Notocallista (Fossacallista) singletoni n.sp., holotype, × 1¼.

Rohea trigonalis (Marwick). Plate 10, figs. 4–6. 1927. Paradione (Notocallista) trigonalis Marw., Trans. N.Z. Inst., vol. 57, p. 593, fig. 73. Oligocene: Bed 6b, Clifden (Hutchinsonian). Two topotypes in the Finlay Collection, a right and a fragmentary left valve, have been collected since the original was described. The left valve paratype described in 1927 and showing a hinge like that of parki came from a different horizon (band 7c) from the holotype and has a smaller lunule. It is not a trigonalis but a somewhat flattened parki. References. Cossmann and Peybot, 1911. Conchologie Néogénique de l'Aquitaine, tome 1, livr. 2. Chant and Gale, 1931. Pliocene and Pleistocene Mollusca of California, Mem. San Diego Soc. Nat. Hist., vol. 1. Headley, C., 1913. Studies on Australian Mollusca, Part XI, Proc. Linn. Soc. N.S. Wales, vol. 38, pt. 2. Iredale, T., 1924. Results from Roy Bell's Molluscan Collections, Proc. Linn. Soc. N.S. Wales, vol. 49, pt. 3. " 1929. Strange Molluses in Sydney Harbour, The Australian Zoologist, vol. 5, pt. 4. Jukes-Browne, A. J., 1913. On Callista, Amiantis and Pitaria, Proc. Malac. Soc., vol. 10, pt. 6. " 1914. A Synopsis of the family Veneridæ, Proc. Malac. Soc., vol. 11, pts. 1 and 2. Marwick, J., 1924. The Veneridæ of New Zealand, Trans. N.Z. Inst., vol. 57. Palmer, H. v. W., 1926. The Veneridæ of Eastern America; Cenozoic and Recent, Palæontographica Americana, vol. 1, no. 5. Stewart, R. B. 1930. Gabb's California Cretaceous and Tertiary Type Lamellibranchs, Acad. Nat. Sc. Phil. Spec. Publ., no. 3. Tegland, N. M., 1929. Correlation and Affinities of Certain Species of Pitaria, Univ. Calif. Publ. Bull. Dept. Geol. Sc., vol. 18, no. 10. Woods, N. II., 1931. Pelecypoda from the Abattoirs Bore, including twelve new species, Trans. Roy. Soc. Sth. Aust., vol. 55.