358 RISSOIA. 



R. NIGRA, Krauss. PL 71, fig. 4. 



Imperforate, thin, rather smooth, violaceous or greenish black, 

 apex obtuse ; whorls 5, convex, with deep suture ; lip acute, simple. 



Length, 1*4 mill. 



Algoa Bay, So. Africa. 

 R. LITTORINIFORMIS, Garrett. PI. 71, fig. 5. 



Smooth, pellucid, shining, white; whorls 5, very convex, rapidly 

 increasing, suture deeply impressed, slightly margined ; peristome 

 rather thick. Length, 2 mill. 



Viti Is. 

 R. HYALINA, Garrett. PI. 71, fig. 91. 



Thin, hyaline, shining, white; whorls 6-7, convex, with very fine, 

 crowded, spiral raised stride, crossed by more delicate growth lines ; 

 whorls 6-7, convex, with deep suture ; peristome rather thick, sim- 

 ple, slightly expanded at the base. Length, 6 mill. 



Samoa^ Viti and Paumotus Is. 

 R. MELANURA, Tenison Woods. PI. 71, fig. 7. 



Scarcely perforate, solid, somewhat translucent, smooth, shining, 

 suture impressed, dark olivaceous ; whorls 5, slightly convex, peri- 

 phery obtusely angulated ; aperture anteriorly produced, lip simple. 



Length, 2 mill. 



Tasmania. 

 R. ANGELI, Tenison Woods. PL 71, fig. 11. 



Umbilicated, turbinate conoidal, thin, pellucid, yellowish, with 

 rather sharp crowded growth lines, and thin, slight spiral stride; 

 whorls 5, with well-impressed suture ; aperture rounded, lip thick- 

 ened. Length, 1'5 mill. 



Tasmania. 

 R. CORIACEA, Manzoni. PL 69, fig. 54. 



Scarcely rimate, thin, fragile, coriaceous, longitudinally lamel- 

 larly striate, light yellowish brown; whorls 6, convex, with deep 

 slightly margined, channeled suture, and rapidly increasing; lip 

 thin, simple. Length, 2*6 mill. 



Madeiran Archipelago. 



An abberant form. 



Subsection PARVISETIA, Monts. 1884. 



R. SCILL^:, Seguenza. PL 69, fig. 38. 



Translucent, opaline, very smooth, shining, yellowish, sometimes 

 with darker maculations or streaks; whorls 4, convex, the last 



