154 FISSURELLA. 



Var. biradiata (Frembly) Sowb. PL 35, fig. 3 ; pi. 46, figs. 12, 



13, 14. 



Shell of the same general form as latemarginata, similarly striated, 

 but marked outside with obscure milky-bluish rays, of which one on 

 each side of the perforation is more prominent. 



Valparaiso, Chili; Iquiqui, Peru, 



F. biradiata (Frembly MBS., in) Sowerby, P. Z. S. 1834, p. 124 ; 

 Conchol. Illust., f. 23, 52. — Reeve Conch. Icon., f. 20. — Sowerby 

 Thes. Conch, iii, p. 185, f. 1-3. — F. galericulum Reeve Conch. Icon., 

 f. 77. 



F. galericulum Rve. (pi. 39, fig. 93) is the same. Fully adult 

 examples scarcely show the two side rays, but the obscure rays over 

 the whole disk usually persist. Other specimens lose all rays when 

 old, the younger shells having only the two side streaks. 



Var. cumingii Reeve. PI. 30, fig. 1. 



" Radiately ribbed, ribs obtuse, unequal, obscurely squamately 

 nodose ; purplish ash or rust color, rayed with deep purple, white 

 around the orifice, sprinkled with a few obscure dots ; basal margin 

 very broad, fulvous ash, blotched with purple." (Rve.) 



Quintero, Chili. 



F. Cumingii Rve. Conch. Icon., f. 17, 1849. — Sowerby, Thes. 

 Conch, iii, p. 187, f. 5, 132. 



The specimens before me differ from latemarginata in having 

 coarser radiating stria?, in being rayed, and in the color of the broad 

 basal margin inside, which is of a grayish tint tessellated with dull 

 red, instead of being uniform deep brown as in the typical late- 

 marginata. 



Group of F. crassa Lam. 



F. crassa Lamarck. PI. 34, figs. 51, 52, 53. 



Shell oblong, depressed, with subcentral summit. Surface smooth 

 except for broad, low, scarcely perceptible radiating waves, more 

 prominent at the front end. Perforation sole-shaped, narrowed a 

 little in front of the middle, one-sixth to one-eighth the length of 

 the shell, the margins eroded around each end of the hole. 



The outline is oblong, a trifle narrower in front, the sides about 

 parallel. It is solid and thick, lusterless, of a brownish fawn-color. 

 The interior is pink within the muscle-impression, and in front of the 

 hole and at its sides there are strong converging wrinkles or fur- 



