GASTEROPODA 201 



four minute widely and equally spaced striations. Spire conical, about i| times height 

 of aperture, outline of whorls strongly convex. Aperture ovate. Peristome discon- 

 tinuous, thin. Columella vertical, arcuate, separated from the base by a narrow 

 umbilical chink. 



Height 1-2 mm.; diameter o-8 mm. (Holotype). 



Habitat: Off Three Kings Islands, St. 933, 260 m. 



Superficially very close to N. tenuisculpta Powell (1933, Rec. Cant. Mas., iv, p. 37) 

 from 170 fathoms off the Bounty Islands, but differing in having more strongly convex 

 whorls, a wider umbilical chink, and the presence of distant microscopic spiral striae 

 upon the protoconch. The nucleus of Notosetia is smooth, but otherwise subtenuis is 

 quite typical of the genus, and may thus be placed there provisionally. 



Notosetia aupouria, n.sp. (Plate LIII, fig. 12). 



Shell very small, ovate-conical, thin, translucent, colourless. Whorls 5J, including a 

 small smooth dome-shaped protoconch of two smooth whorls. Spire tall, about \\ times 

 height of aperture. Outline of spire whorls lightly convex, body whorl rounded at 

 periphery and on base. Post-embryonic whorls sculptured with very fine spiral stria- 

 tions: fourteen on penultimate whorl increasing to about twenty-four on the body 

 whorl, between the suture and a peripheral thread. The base at first appears to be 

 smooth, but under a higher magnification shows dense exceedingly fine striations. 

 Aperture ovate, angled above. Peristome thin, discontinuous. Columella vertical, 

 straight. No umbilical chink. Basal lip very shallowly and broadly notched. 



Height 1-9 mm.; diameter 1-25 mm. (Holotype). 



Habitat: Off Three Kings Islands, St. 933, 260 m. 



Related to Suter's infecta from Lyall Bay and elsewhere in the south, but differing 

 from that species in being proportionately broader and in having dense spiral striae 

 over the whole of the post-nuclear whorls. 



Family RISSOINIDAE 



Genus Rissoina, d'Orbigny, 1840 



Type (by monotypy) : Rissoina inca, d'Orbigny. West Coast, South America 



Rissoina aupouria, n.sp. (Plate LIII, fig. 6). 



Shell rather large for the genus, elongate-conic, gracefully tapered. Spire tall, about 

 if height of aperture. Whorls eight, including a protoconch of two smooth whorls. 

 Post-nuclear sculpture of closely packed weak axial ribs and microscopic interstitial 

 spiral threads. There are thirty-four axials on the penultimate whorl and they are about 

 their own width apart. The spiral threads are very numerous and closely spaced over 

 the spire whorls, but open out a little over the base. Aperture oblique, ovate, chan- 

 nelled above and below. Peristome continuous, outer lip, basal lip and columella heavily 

 calloused. Colour bright yellowish brown, protoconch and apertural callus white. 



