RISSOIA. 349 



R. GLAPHYRA, Watson. PL 64, fig. 97. 



Scarcely perforate, thin, hyaline, white, apex blunt, suture nar- 

 rowly margined, slightly impressed ; whorls 5, very feebly ribbed at 

 the -suture of the body whorl, very faintly, spirally flat-ridged and 

 furrowed ; outer lip thin and sharp. Length, 1/5 mill. 



Off Nightingale IsL, Tristan da Cunha; 100-150 fms. 

 R. MONIZIANA, Watson. PL 63, fig. 80. 



Umbilicated, rather thin, frosted (not glossy), transparent, 

 slightly longitudinally puckered beneath the suture; whorls 4-5, 

 convex, with a narrow, sloping shoulder, spirally ridged, ridges on 

 body whorl 7-9; lip subexpanded, thick. Length, 1'75 mill. 



Madeira Is. 

 R. CASTANEA, Holler. PL 63, fig. 77 ; PL 64, figs. 95, 96. 



Imperforate, opaque, chestnut color, apex obtuse ; whorls 4i , 

 convex, with impressed suture, and distinctly angulate, about 12 

 lines on the last whorl. Length, 4 mill. 



Norway, Iceland, Greenland, JBehring's Sea, Gulf of St. Lawrence. 

 Var. ALASKANA, Ball. Fig. 96. 



Thinner, with rather prominent sutural wrinkles, smaller, with 

 same number of whorls. Under the pale, yellowish epidermis, the 

 shell is pinkish. Length, 2'5 mill. 



Behring's Sea. 

 R. CASTANELLA, Dall. PL 64, fig. 93. 



Whorls 5, convex, spirally ridged, about 6 to 12 on the body 

 whorl, varying in number ; narrowly umbilicated ; peritreme con- 

 tinuous, slightly thickened ; pinkish or brownish white under the 

 epidermis. Length, 2'7 mill. 



Behring's Sea. 

 R. AURIVILLII, Dall. PL 64, fig. 94. 



Narrowly umbilicated, waxen or yellowish ; whorls 5i-6, with 

 strong spiral ridges and concave, much wider interspaces, there are 

 about 8 ridges on the body whorl ; lip continuous, slightly thick- 

 ened. Length, 4'3 mill. 



Aleutian Is. 

 R. GRISEA, Martens. PL 68, fig. 92. 



Scarcely umbilicated, semipellucid, reddish grey, whitish near the 

 aperture, under an ash colored, caducous epidermis ; whorls 4, con- 

 vex, with low spiral cingulse, separated by narrow impressed stria3 ; 

 lip thickened, interior orange-corneous. Length, 2*25 mill. 



South Georgia. 



