344 GASTROPODA. [Pectinibranchia. 



the first two whorls, the interstices linear, the sculpture extending over 

 the base ; growth-lines dense, oblique, distinct. Colour white. Spire 

 elevated conic, about twice the height of the aperture ; outlines straight. 

 Protoconch minute, heterostrophe, globular. Whorls 5, regularly in- 

 creasing, flatly convex, the last not angled ; base flattish. Suture 

 impressed. Aperture slightly oblique, angled above and narrowly 

 produced below. Outer lip regularly rounded, thin and sharp. Colu- 

 mella subvertical, almost straight, with a minute plait above. Inner 

 lip extending a short distance beyond the pillar, and as a thin layer 

 over the parietal wall. Operculum unknown. 



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



Animal unknown. 



Type in my collection. 



Hab. Port Pegasus, Stewart Island, in 18 fathoms, type (Captain 

 Bollons). 



Remarks. This species is nearest allied to 0. impolita, but it is a 

 smaller and more slender shell, and the spiral sculpture is much more 

 distinct. The fossil 0. fasciata, Hutt. == Huttoni, Sut., is also very 

 similar, but has a differently arranged sculpture and an open um- 

 bilicus. 



Subgen. 3. PYRGULINA, A. Adams, 1863. 



Pyrgulina, A. Ad., J.L.S., vii, 1803, 4. Type: Cliryscdlida casta, A. Adams. 

 Parthenia, Lowe, 1840 (in part). Noemia, Folin, 1870. Parthcnina, 

 Bucq., Dollf., Dautzenb.. 1883. 



Shell with axial ribs, the post-nuclear whorls sculptured similarly 

 throughout ; spiral markings consisting of impressed lines, subequally 

 spaced, present between the sutures and the base of the whorls. 



19. Odostomia rugata, Hutton, 1886. Plate 17, fig. 8. 



Odostomia (Parthenia) plicata,''H.utt., T.N.Z.I., xvii, 1884 (1885), 319, pi. 18, 

 f. 17 ; not of Montfort, 1810. 0. rugata, Hutt., T.N.Z.I., xviii, 1885 

 (1886), 353 ; Plioc. M., 58, pi. 7, f. 51. O. (Pi/rgulina) rugata, Hutt. : 

 Murdoch, T.N.Z.I., xxxvii, 227. 



Shell small, ovato-elongated, imperforate, rather solid, somewhat 

 shining, axially plicated. Sculpture consisting of numerous oblique 

 flatly rounded axial riblets, usually stopped by a spiral thread below 

 the periphery of the last whorl, but very often extending over the 

 base ; the riblets on the last volution sometimes, though rarely, almost 

 vertical ; interstices of about the same width as the riblets, and adorned 

 with minute dense spiral striae ; the riblets number about 18 on the 

 body-whorl. Colour white. Spire elevated conical, about twice the 

 height of the aperture ; outlines almost straight. Protoconch minute, 

 of 1 smooth whorl, heterostrophe, nucleus lateral. Whorls 6, regu- 

 larly increasing, flatly rounded ; base convex. Suture impressed and 

 slightly margined. Aperture subvertical, ovate, angled above, slightly 



