Rissoa.] GASTROPODA. 209 



Diameter, 0-8 mm. ; height, 1-5 mm. 



Animal unknown. 



Type in my collection. 



Hah. Titahi Bay, Cook Strait, type (Miss Mestayer). 



16. Rissoa rosea, Hutton, 1873. Plate 12, fig. 16. 



Rissoa rosea, Hutton, C.M.M., 29. Barleeia rosea. Hutton, M.X.Z.M., 81 ; 

 Man. Conch. (1), ix, 393, pi. 71, f. 6 : Sut.-r. P. Mai. S., iii, 8. 



Shell minute, ovate, imperforate, smooth, polished. The only 

 sculpture consists of very fine oblique growth-striae. Colour uniformly 

 pink. Spire elevated conic, higher than the aperture, outlines 

 straight. Protoconch small, globular, of 1J smooth rounded whorls. 

 Whorls 5, regularly increasing, flatly rounded ; base slightly convex. 

 Suture moderately impressed. Aperture roundly ovate, subangled 

 above. Peristome continuous, very little thickened. Columella arcuate, 

 vertical, slightly callous, white. Operculum unknown. 



Diameter, 1-8 mm. ; height, 2-3 mm. 



Animal unknown. 



Type in the Dominion Museum, Wellington. 



Hab. Stewart Island (type) ; Port Pegasus, Stewart Island, in 

 18 fathoms (Captain Bollons) ; Whangaroa Harbour (C. Traill) ; near 

 the Snares and Bounty Islands, in 50 fathoms, and Taumaki Island, 

 South Island, in 10 fathoms (Captain Bollons) ; Dusky Sound, in 

 30 fathoms (R. Henry) ; Auckland Islands (Professor Benham). 



17. Rissoa roseocincta, Suter, 1908. Plate 12, fig. 17. 

 Rissoa roseocincta, Suter, P. Mai. S., viii, 29, pi. 2, f. 26 



Shell minute, ovate, rimate, thin, polished, translucent, with pink 

 and white spiral bands. There is no sculpture, except for fine micro- 

 scopic oblique growth-lines. Colour : The first 3 whorls are pink, the 

 last whitish with a narrow pink band below the suture, a second just 

 below the periphery, and a third upon the base ; sometimes the last 

 whorl is also pinkish, and the lighter cinguli are only faintly visible. 

 Spire conical, higher than the aperture ; outlines a little convex. 

 Protoconch small, broadly rounded, smooth. Whorls 4, flatly rounded, 

 the last rather large and somewhat inflated ; base convex. Suture not 

 deep. Aperture vertical, roundly oval, slightly angled above. Peri- 

 stome continuous in adult specimens, thin on the parietal wall, slightly 

 thickened, sharp. Columella short, subvertical ; the inner lip slightly 

 expanded, and giving rise to a narrow chink. Operculum unknown. 



Diameter, 0-9 1-0 mm. ; height, 1-6-1 -5 mm. 



Animal unknown. 



Type in my collection. 



Hab. Titahi Bay, Cook Strait, type (Miss Mestayer). 



Remarks. The nearly allied R. rosea, Hutton, is larger, more 

 solid and opaque, uniformly pink ; the outlines of the spire are straight 

 and the whorls flat. 



