220 GASTROPODA. [Pectinibranchta. 



of the aperture ; outlines straight. Protoconch small, dome-shaped. 

 Whorls 5, flatly convex, the last volution high ; base convex. Suture 

 not deep. Aperture oblique, oval, angled above. Peristome con- 

 tinuous, slightly thickened, the edge rather blunt, thin on the parietal 

 wall. Basal lip slightly expanded. Columella oblique, almost straight, 

 very thin. Operculum unknown. 



Diameter, 1-5 mm. ; height, 3-3 mm. 



Animal unknown. 



Type in my collection. 



Hab. Hauraki Gulf (H. S.). 



Remark. A species allied to R. rugulosa, Hutt., but much smaller, 

 and lacking spiral sculpture. 



3. Rissoina rugulosa, Hutton, 1873. Plate 13, fig. 10. 



Rissoa rugulosa, Hutton, C.M.M., 28. Rissoina rugulosa, Hutton, M.N.Z.M., 

 80; Suter, P. Mai. S., iii, 6. Eulima chathamensis, Hutton, C.M.M., 23. 



Shell small, elongated oval, imperforate, solid, costate. Sculpture 

 consisting of oblique rounded axial riblets, obsolete upon the base, 

 15-16 on the penultimate whorl ; interstices a little wider than the 

 riblets, finely spirally lirate, the lirae slightly stronger and more con- 

 spicuous on the base. Colour yellowish-brown, rarely with a few 

 lighter bands on the 2 lower whorls ; or white or yellowish-white, 

 occasionally with a few light-brown spiral bands on the last 2 whorls ; 

 apex and base of lighter colour. Spire high, conic, much higher than 

 the aperture ; outlines slightly convex. Protoconch globose, of 2 

 smooth, convex, and glossy whorls. Whorls 7-8, flatly rounded, 

 regularly increasing ; base convex. Suture impressed. Aperture 

 oblique, ovate, angled above and distinctly channelled below the 

 columella. Peristome continuous, much thickened, white, rounded. 

 Columella very short, oblique. Operculum typical. 



Diameter, 3 mm. ; height, 7-5 mm. 



Animal unknown. 



Type in the Dominion Museum, Wellington. 



Hab. Stewart Island (type) ; Bay of Islands ; Hauraki Gulf ; 

 Chatham Islands ; Taurnaki Island, South Island, in 10 fathoms 

 (Captain Bollons) ; Banks Peninsula (Iredale). 



Remarks. This species closely approaches R. Hanleyi, Schwartz 

 ( = R. variegata, Angas), R. lirata, Angas, and R. Angasi. Pease ( = R. 

 turriculata, Angas), from Australia, but I do not think it is conspecific 

 with any of them. It certainly is distinct from R. Hanleyi. Good 

 series of the Australian species are wanted to settle the question, and 

 these are not at my disposal. 



The shell is sometimes covered with a black coating. 



Fossil in the Pliocc.no. 



