284 MAZATLAN UNlVAtVES 



1409, 1 sp. finely developed, witli coloured rays, laminae con- 

 centrically striated. 



Aberrant specimens. Tablet 1410 contains 1 sp. longitudin- 

 ally ribbed (from adlierent surface.) — 1411, 7 sp. margin 

 irregular. — 1112, 3 sp. margin curved. — 1413, 3 sp. flat and 

 recurved, form of C. imguiformis.— 1414, G sp. posterior margin 

 expanded. — 1415, 3 sp. subspiral, approaching C. aculeata. — 

 1416, 1 sp. deck elongated.— 1417, 3 do. deck very sbort.— 1418, 

 3 do. colour developed inside, brown passing into green. — 1419, 

 1 sp. sliewing under layer of deck, striated.— 1420, 1 do. dis- 

 eased. — 1421, 1 do. deck solid, as in C. onyx.— 1422, 1 do. flat, 

 concentric striae conspicuous.— 1423, 3 do. longitudinally cor- 

 rugated. 



Tablet 1424 contams a portion of Spondylus calcifer, pre- 

 sented by E. D. Darbiskire, Esq. containing in situ 4 sp. 

 Petricola robusta, 1 Cumingia, 2 Litbopbagus plumula, 1 G-as- 

 trochaena truncata, and 1 Crepidula nivea. This is greatly 

 elongated, 1*55 by "72, much arched, and with very numerous 

 layers. Its position in a burrow of Lithophagus has preserved 

 the apex from detrition.— 1425, 1 sp. still more elongated, from 

 the burrow of a Lithophagus in Chama, closely resembling 

 C. explanata, Gould. 



Specimens shelving decTc margin. Tablet 1426 contains 3 sp. 

 sinus slight, center more or less deeply augulated. — 1427, 6 sp. 

 sinus deep, center nearly straight, more or less angulated or 

 sinuated.— 1428, 1 sp. with abnormal central ridge. 



Tablet 1429 contains 2 young shells which probably belong 

 to this species, though the apex has been rubbed smooth. 



342. Ceepidttla Pcngitifoemis, Lam. 



Patella crepidula, Linn. S//st. ^at. p. 1257, no. 7o2.—I>illw. 



Bescr. Cat. p. 1021, no. 13. 

 Crepidula unguiformis. Lam.. An. s. Vert. vol. vii. p. 642, 



no. 4.— i?/W. Fruc. Zool. Soc. 1834, ^.Z'd.— C.BAd.Pan. 



SJwlls, p. 230, no. 350.— (lanacus u.) H. Sf A. Ad. Gen. i. 



p. 370. 

 Crepidula Italica, L>efr. Diet. Sc. Nat. Tol. xi. p. 397. 

 Crepidula plana, Sai/, Journ. Ac. Nat. Sc. Phil. vol. ii. p. 226. 



(teste Gould 4" C. B. Ad. non Desk.) 

 Comp. Patella Goreensis, Gmel. p. 3694.— J>/7Z?i'. Descr. Cat. 



p. 1020, no. 12.— (Crepidula G.) Desk, in Lam. An. s. Vert. 



