MAZATLAN UNIVALVES 219 



which the hole preserves the normal characters, measures 



long. '48, lot. '3, alt. '15. 



The largest sp. (elongated) ;1'67, 1*06, '6. 



A normal sp. 1'56, 1'08, '62. 



A conical sp. 1*34, *96, *62. 

 Hole of largest sp. '3 by '12. Div. 95 by 105. 

 Hob. Mazatlan ; common ; L'pool Col. 



Tablet 1058 contains 8 sp. different ages, normal state. -1059, 

 3 sp. elongated. 1060, 3 do. smooth. 1061, 3 do. elevated, 

 nodulous. 1062, 4 sp. shewing interior. 1063, 3 sp. with singu- 

 lar growth of coralline. 1064, 1 do. smooth, with Acmaea 

 mitella in situ. 1065, 1 do. nodulous, with dried animal of 

 adherent limpet. 2066, 2 sp. hole abnormally produced, 

 (div. 85.) 1067, 3 sp. withBalani, and attachments of limpets. 

 In one (empty), a young Isognomon has taken up its abode. 

 Another (spinous) has inserted a fang through the hole of the 

 shell. 1068, 3 sp. distorted growth. 



SECTION B. Margin smooth. 



277. FlSSTJBELLA PERTJVIANA, Lam. 



Lam. An. s. Vert. vol. vii. p. 599, no. 17. J?. M. Cat. D'Orb. 



Moll. p. 51, no. 432. 

 + Fissurella subrotundata, Desk. JEW. Meth. Vers, vol. ii. 



p. 135, no. 11 1 Lam. An. s. Vert, vol vii. p. 602, no. 26. 

 Var. = Fissurella affinis, Gray, Proc. Zool. Soc. 1834, p. 125. 



Sow. Conch. HI. p. 4, no. 35, f. 44. 

 Cremides Peruviana, H. fy A. Ad. Gen. i. 446. 



Only one specimen, and that somewhat worm-eaten, was 

 found of this characteristic S. American shell. * Shell very 

 conic, slightly ribbed, hole nearly round, anterior side pointed, 

 inside white, with a sharp, non-crenated, narrow margin, 

 shaded with purplish brown. Long. 1*35, lat. 1'12, alt. *68. 

 Hob. Peru, jHumboldt fy Bonpland. Is. Mexillones, Lobos; 



Iquiqui and Valparaiso ; Cuming. Mazatlan ; 1 specimen ; 



L'pool Col. 



Tablet 1069 contains the specimen. 



278. FlSSURELLA SPONGIOSA, n. S. 



F. t. elongatd, compressd, conicd, antice angiwtiore, postice ' 

 dilatata ; superficie externd quasi spongiosd, nee liratd nee 

 striatd ; viridi, juniore lineis, advltd maculis castaneis radi- 



