I 



MAZATLAN UNIVALVES 219 



which the hole preserves the normal characters, measures 



long. '48, lat. "3, alt. '15. 



The largest sp. (elongated) „ V&J, „ 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". 

 JIab. — 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 Acmsea 

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

 adherent limpet. — 2068, 2 sp. hole abnormally produced, 

 (div. 85".)— 1067, 3 sp. with Balani, and attachments of hmpets. 

 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. FiSSTTEELLA PERUVIANA, Lam. 



Lam. An. s. Vert. vol. vii. p. 599, no. 17.— 2?. M. Cat. D'Orb. 



Moll. p. 51, no. 432. 

 + FissnreUa subrotundata, Besh. JSnc. Meth. Vers, vol. ii. 



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

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



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

 Cremides Peruviana, S. Sf A. Ad. Gen. i. 446. 



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

 found of this characteristic S. American shell. Shell veiy 

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

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

 shaded with purplish brown, io??//. 1' 35, lat.l'\2, alt. 'G8. 

 JTab.—Vevxi, Humboldt Sf Bonpland.— Is. Mexillones, Lobos; 



Iquiqui and Valparaiso ; Cuming. — Mazatlan ; 1 specimen ; 



L'pool Col. 



Tablet 1069 contains the specimen. 



278. FiSSUBELLA 8PONGI08A, M. S. 



F. t. elongatd, compres.^d, conicd, atitice angu.'stiore, postictf 

 dilatatd ; superjicie externa quasi .<^pongiosd, nee liratd nee 

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



