224 GASTROPODA. [Pectinibranchia. 



impressed. Aperture subvertical, oval, angled above. Peristome con- 

 tinuous, simple, straight and sharp, very little callous inside. Colu- 

 mella short, arcuate. Inner lip slightly expanded towards the verv 

 slight umbilical depression. Operculurn horny, rather thin, with an 

 oblique claviform inner process. 



Diameter, 1-5 mm. ; height, 2-7 mm. (type). 



Dentition. Central tooth rhomboidal, with 5 denticles, the mesial 

 larger than the others. Lateral tooth elongated, with a broad short 

 reflection and 5 small cutting-points, the middle one largest. First 

 marginal with 3 subequal denticles, the second with 2 sharp minute 

 hooks at the apex, the upper one with a number of very small cutting- 

 points. 



Type in the Canterbury Museum, Christchurch. 



Hob. Campbell Island, type (Professor Chilton) ; Auckland Islands 

 (Captain Bollons). Specimens from the latter locality are also in the 

 British Museum. 



9. Rissoina cuvieriana, Suter, 1908. Plate 13, fig. 16. 



Rissoina cumeriana, Suter, T.N.Z.I., xl, 1<>07 (1908). 345, pi. 27, f. 3. 



Shell small, ovate, imperforate, thin and fragile, pellucid, some- 

 what shining. Sculpture consisting of very fine oblique growth-lines, 

 crossed by microscopic fine and close spiral striae, very faint on the 

 spire-whorls. Colour yellowish-brown, with a darker band below the 

 suture and upon the umbilical tract. Spire conical, slightly higher 

 than the aperture ; outlines almost straight, Protoconch small, whorls 

 convex and smooth. Whorls 6, convex, the last of considerable size ; 

 base rounded. Suture not much impressed. Aperture oblique, oval, 

 angled above, distinctly effuse below. Peristome discontinuous, simple, 

 sharp. Columella vertical, somewhat concave, white. Inner lip not 

 reflexed, with a sharp edge, spreading as a thin white callosity over the 

 parietal wall. Operculum unknown. 



Diameter, 3-5 mm. ; height, 5-8 mm. 



Animal unknown. 



Type in my collection. 



Hab. Five miles south of Cuvier Island, in 38 fathoms (Captain 

 Bollons). One specimen. 



Remark. --In coloration this species resembles the much smaller 

 R. fuscozona, Sut. 



10. Rissoina fuscozona, Suter, 1908. Plate 13, fig. 17. 



Rissoina fuscozona, Suter, P. Ma!. S., viii, 32. pi. 3. f. 3-i. 



Shell small, elongately oval, imperforate, thin, smooth, shining, 

 semitransparent. Fine, oblique growth-lines form the only sculpture. 

 Colour fulvous, a dark-brown band below the suture, peristome fuscous. 

 Spire elevated conic, twice the height of the aperture ; outlines 



