LUCAPIXELLA. 197 



or a little concave, the posterior slope concave. The two sides of 

 the fissure project upward in more or less salient points. The 

 sculpture consists of alternately larger and smaller radiating riblets, 

 crossed by sharp, concentric laminae, elevated into imbricating 

 scales on the ribs. The blackish rays sometimes cover most of the 

 surface, sometimes are narrow and few. Inside bluish-white, with 

 a rather wide callus rim around the fissure; lateral edges blunt, 

 ends slightly crenulated. In immature specimens the edges are 

 crenulated. Length 19, breadth 10, alt. 4§ mill. 



Lobltos and San Diego, CaL, to San Ignacio Lagoon, Lower Cal., 

 in about 6 fms. 



Clypidella callomarginata (Cpr.) Dale, Amer. Journ. Conch. 

 1872, p. 133, t. 15, f. 8. 



The animal is described under the generic head. When stand- 

 ing on a plane surface the broad posterior extremit}' is seen to be a 

 little elevated. The sculpture is very sharp and beautiful. 



L. ^qualis Sowerby. PI. 31, fig. 24. 



Shell oblong-ovate, rather thin, depressed, decussated with dis- 

 tant obtuse radiating and concentric stria?; orifice ovate, rather 

 large ; ashy-black, rayed with white. Unusually thin and depressed, 

 with a rather large orifice. {Reeve.) 



St. Elena, West Coast S. America. 



Fissurella cequalis Sowerby, P. Z. S. 1834, p. 127; Conchol. 

 Illustr., f. 56. — Reeve, Couch. Icon. f. 55. — Fissurellidea cequalis 

 Sown., Thes. Conch, iii, p. 203, f. 200. 



A species not seen by me, probably grouping with callomarginata. 



L. aculeata Reeve. PI. 36, fig. 19. 



Shell oblong-ovate, slightly attenuated anteriorly, depressed, 

 rather elevated in the middle, radiately finely ribbed, concentric- 

 ally laminated, lamina? elegantly prickly-scaled ; orifice ovate, 

 large ; fawn-white. The radiatiug ribs of this elegant species are 

 almost wholly formed of elevated prickly scales. (Rve.) 



Habitat unknoivn. 



F. aculeata Reeve, Conch. Icon. f. Ill, 1850. — Sowerby, Thes. 

 Conch, iii, p. 201, f. 186. 



This and the next species may possibly prove identical ; but the 

 more anterior position of the orifice perhaps indicates G/yphis 

 rather than Lucapinella. In the absence of information regarding 

 the inside, the generic positions of many species are problematical. 



