FISSURELLA. 155 



rows. The muscle-impression itself is yellowish in color, and is 

 roughened at its posterior curve. There is a narrow brown margin. 

 Length 85, breadth 52, alt. 16 mill. 



Chili. 



F. crassa LAM. Anim. s. Vert, vi, 2d pt., p. 11, 1822. REEVE, 

 Conch. Icon. f. 4. SOWERBY Thes. Conch, iii, p. 184, f. 15, 16. 

 SOWERBY, Conchol. Illust., f. 11. 



The measurements of an average specimen are given above. The 

 pink interior, wrinkled as if guttered by running water (as indeed it 

 probably is) is very characteristic. 



Group of F. peruviana Lam. 



Smaller shells than those of the preceding groups, of a conical 

 shape, and having a narrow but well-defined dark border inside. 

 The few species range from Peru and the Galapagos Islands to 

 California. 



F. PERUVIANA Lamarck. PI. 33, figs. 41-45 ; pi. 42, fig. 57, 58, 59. 



Shell rounded-oval, elevated, conical, the orifice a little in front 

 of the middle ; radiately finely striated ; perforation small ; oval, 

 about one-tenth the length of the shell ; inside white, margin alter- 

 nately red and gray. 



The form is conical, elevated, lateral slopes nearly straight. It 

 is rather thin, finely radiately striated ; inside smooth ; margin 

 smooth, narrowly bordered. Color blood-red toward the summit, 

 becoming darker, more purplish below, and generally more or less 

 rayed with deep purple. The radiating stride are not equal in size, 

 from 3 to 7 smaller ones intervening between slightly larger riblets. 

 On some specimens this inequality is more marked. 



Length 35, breadth 30, alt. 18 mill. 



Length 26, breadth 21, alt. 10 mill. 



San Antonio, mouth of the Rio Maipa ; S. Lorenzo ; and Callao, 

 Peru. 



F. peruviana LAM. An. s. V. No. 17. REEVE, Conch. Icon. f. 

 26. SOWB. Thes. Conch, iii, p. 185, (not F. peruviana Deles- 

 sert, Recueil, t. 24, f. 7 !) F. subrotunda DESK, in Encyc. Meth. and 

 2d. edit, of Lamk. vii, p. 602. F. affinis GRAY, P. Z. S. 1834, p. 

 125. SOWB., Thes. Conch, iii, p. 185, f. 42, 179. Conch. Illust., f. 

 44. F. occidens GOULD, Proc. Bost. Soc. N. H. ii, p. 156, 1846 

 Exploring Expedition Shells p. 364, figs. 473. 



