FISSURELLA. 153 



F. MEXICANA Sowerby. PI. 34, fig. 60. 



Shell oblong, reddish-brown with darker rays and numerous close- 

 set radiating grooves, which are decussated by very fine concentric 

 striae ; dorsal aperture oblong, rather contracted in the middle, and 

 with two obsolete teeth on each side ; inside white with a purple- 

 brown crenulated margin. (Sow.) 



Length 1'25, breadth 0'56 inches. 



Real Llejos, Mexico. 



F. Mexicana Sow. Conch. 111. Fissurella p. 8, fig. 61. REEVE, 

 Conch. Icon. f. 40. SOWERBY, Thes. Conch, iii, p. 186, f. 26, 27, 



28, 78. 



The orifice, says Reeve, has a very decided white border. I have 

 not seen authentic examples. Compare F. oriens Sowb. The local- 

 ity needs confirmation ; for, as I have shown on page 143 , the spe- 

 cies of this group do not extend above Peru. 



F. LATEMARGINATA Sowerby. PL 32, figs. 36, 37, 38. 



Shell depressed, ovate, narrower anteriorly, summit a trifle in 

 front of the middle ; radiately finely striated all over. Perforation 

 oblong, twice as long as wide, with straight, parallel sides, its length 

 contained 8 times in the total length of the shell. 



The shell is depressed, egg-shaped in outline, the front part being 

 narrower ; it is solid, of a uniform reddish purple color outside, 

 white with a broad dark purple or chocolate border inside. The in- 

 terior has indistinct radiating fine striae. The muscle-impression is 

 quite broad, and is near to the wide dark margin. The sides are a 

 little arched, so that when resting on a flat surface the ends alone 

 support the shell. 

 . Length 68, breadth 50, alt. 12 mill. 



Length 69, breadth 49, alt. 11 mill. 



Chili; Peru. 



F. latemarginata Sow. P. Z. S. 1834, p. 126 ; Conchol. Illust., f. 

 69. REEVE, Conchol. Icon., f. 19. SOWERBY, Thes. Conch, iii, p. 

 185, f. 6, 7, 12. 



The broad purple border of the interior, and fine striation and 

 uniform color of the outside are characteristic. 



