The embryo is planorboid and rather curiously tilted. The general habit of the shell is at once distinctive, and there can be no confusion with other Odostomid groups. Spiral sculpture is present in the form of irregular, weak microscopic striations, but this is not necessarily of more than specific significance. Key to Species of Gumina. Shell large, body-whorl capacious; microscopic spiral striae indistinct; whorls lightly convex; spire slightly staged. dolichostoma Shell small, more slender; body-whorl not so capacious; microscopic spiral striae well developed; whorls more strongly convex; spire not staged, but suture well impressed. minor Gumina dolichostoma (Suter). (Fig. 10.) 1908. Odostomia dolichostoma Suter, Trans. N.Z. Inst., vol. 40, p. 365, pl. 29, fig. 11. 1913. Odostomia dolichostoma Suter, Man. N.Z. Moll., p. 336, pl. 16, fig. 18 (Atlas). 1928. Gumina dolichostoma (Suter). Finlay, Trans. N.Z. Inst., vol. 59, p. 260. Suter's types are but immature shells, for the writer has from Takapuna, which is practically the type locality, an adult specimen of considerably greater size (see dimensions below). Height, 4·0 mm.; width, 2·0 mm. (holotype). Corresponding dimensions of a specimen from Takapuna Beach: 6·6 mm.; 3·3 mm. Localities: Cheltenham Beach, Auckland (type); Takapuna Beach, Auckland; Spit Beach, Otago Harbour; Chatham Islands. Type in Wanganui Museum. Gumina minor Laws. 1940. Gumina minor Laws, Trans. Roy. Soc. N.Z., vol. 70, p. 53. pl. 6, fig. 16. Localities: Mangapani, near Waitotara (Pliocene), type; Nukumaru (Nukumaruan); Awanui Bay, in 12 fathoms; Doubtless Bay, in 12 fathoms. Type in writer's collection. Genus Sinuatodostomia Nomura. 1937. Nomura, Saito Ho-on Kai Mus. Res. Bull., no. 13. p. 23, pl. 6, figs. 24a. 24b. Type (o.d.): Odostomia sinuosa Nomura. Recent, Japan. The definition of this genus (instituted by Nomura as a subgenus of Odostomia) is as follows: “Odostomia having a distinct subsutural sinus at aperture. The surface marked by many very distinct flexuose growth lines, crossed by numerous microscopic spiral striae.” Sinuatodostomia neozelanica n.sp. (Fig. 8.) Shell very small, outlines straight, sutures strongly cut in, whorls lightly convex to flat, height of body-whorl less than half that of shell. Protoconch heterostrophic, large, heavy, its lateral nucleus coiled in a high helicoid spiral and overhanging first adult volution. Surface worn so that minute sculpture, if originally present, has been obliterated. Periphery angulated. Aperture broadly ovate; columella thin, a little arcuate, with a light fold above. Umbilical perforation present. The most interesting feature of this shell is the very distinct subsutural sinus on outer lip. The entire outer lip is well preserved