HELCIONISCUS. 135 



Jap. p 156. DEBEAUX, in Journ. de Conchy]. 1863, p. 245. P. 

 granostriata REEVE, Conch. Icon. f. 126. 



This species is extremely variable in degree of elevation. It is 

 never so variegated as P. toreuma, is more elevated, thicker, and 

 the fine riblets are distinctly, finely and regularly beaded. From the 

 Japanese species of Acmcea which have similar sculpture, it is of 

 course separated by the lack of a defined internal border to the lip- 

 edge. 



I am now disposed to consider Patella granostriata Reeve as a 

 synonym of amussitata. 



H. TOREUMA Reeve. PI. 13, figs. 50, 51, 52, 53. 



Shell depressed, long-oval, thin, the apex between the front third 

 and fourth of the shell's length ; front slope straight or concave, 

 posterior slope gently convex. Surface having fine close radiating 

 stride separated by interstices slightly wider than themselves, the 

 striae sometimes a little irregular but not distinctly beaded. Color 

 excessively variable, usually greenish or buff, rayed or blotched 

 with purplish-black and dotted with white ; sometimes without dark 

 markings. 



Interior silvery or bluish, showing distinctly the dark and light 

 markings of the exterior, the central area dusky, white or rich 

 chestnut, its edges not sharply defined. 



Length 40, breadth 31, alt. 9 mill. 



Nagasaki, ToJcio, etc., Japan; China. 



P. toreuma RVE., Conch. Icon. f. 69. LISCHKE, Jap. Meeres- 

 Conchyl. i, p. 109, t. 8, f. 12-15; ii, p. 102, t. 6, f. 12. DKR. Ind. 

 Moll. Mar. Jap. p. 156. 



A thin species, always depressed, remarkable for the endless 

 variety of its mottled coloring. It is allied to P. amussitata, but the 

 delicate riblets or striae are not beaded as in that species. 



P. GRATA Gould. Unfigured. ' 



Shell ovate-conic, elevated, apex acute, very much anterior ; out- 

 side rude, ashen, with elevated compressed radiating ribs which are 

 tubulose toward the margin ; margin expanded, denticulate. In- 

 side ochraceous variegated with brown, spatula and subrnargin 

 intense chestnut. Length 30, width 24, alt. 14 mill. (Gld.) 



North shores of Niphon. 



