280 MAZATLAN TTNIVALVES 



L'pool Col. [C. ? hepatica : Benguela and Loander, very 

 common and variable, Tarns-. Tafel Bay and Natal, XraussJ] 



Tablet 1388 contains 3 sp. very young. 1389, 4 sp. different 

 ages, finely grown. 1390, 2 sp. form approaching C. incurva ; 

 one very dark. 1391, 1 sp. with irregular ridges, passing to 

 the form Lessonii. 1392, 1 sp. twisted, apex lateral. 1393, the 

 largest specimen. 1394, 1 sp. light coloured, slightly rayed 

 with darker. 1395, 1 sp. very light coloured, beginning con- 

 vex, suddenly becoming flat and slightly rayed in the middle. 



Tablet 1396 contains 2 young sp. var. Lessonii, probably 

 belonging to this species, but perhaps to C. nivea. 



^ 341. CBEPIDULA NIVEA, C. B. Ad. 



Cr. t. ellipticdj subrotundatd, seu maxime elongatd ; tenui, 

 sew incrassatd ; intus nived, lineis castaneis radiantibus scepe 

 ornatd; sublcevi, seu irregulariter concentrice plus minusve 

 rugosd, seu lamellis extantibus varie instructd ; limbo acuto, 

 seu maxime planato, lamelloso ; epidermide copiosd irregulari- 

 ter lamellosd ; superficie seu striulis coneentricis seu (sub lente) 

 rugulis radiantibus varie ccelatd ; habitu incrementi vix spirali ; 

 vertice nucleoso, minimo, Velutince simili, apicem monstrante, 

 castaneOj rare albo, rugis coneentricis conspicuis instructo, satis 

 prominente, spiraliter subito augente, dextrorsum deflecto, amar- 

 gine vix remoto, scepe ad marginem vecto et detrito ; septo plus 

 minusve in medio angulato seu sinuato, ad sinistram partem 

 plus minusve prof unde, ad dextr amp arum sinuato, tenui, lineas 

 incrementi, kaud lineam centralem monstrante. 



C. B. Ad. Pan. Shells, 1852, pp. 234, .320, no. 351 : diagn. 



auct. (Crypta n.) H. $ A. Ad. Gen. i. 369. 

 + Calyptrsea (Crepidula) Squama, Brod. Proc. Zool. Soc. 1834, 



p. 40: Trans. Zobl. Soc. vol. i. p. 205, pi. 29, f. W.Miill. 



Syn. Nov. Test. Viv. p. 151. (Crepidula s.) Lam. An. s. Vert. 



vol. vii. p. 648, no. 16. C. B. Ad. Pan. Shells, no. 649, 



p. 229 (lanacus s.) H. fy A. Ad. Gen. i. 370.-^? = Crepidula 



G-oreensis, Mice. Zeit.f. Hal. 1851, p. 36, no. 124. 

 + Crepidula striolata, Wee. Zeit.f. Hal. 1851, p. 35, no. 123. 

 4- Calyptrsea (Crepidula) Lessonii, Brod. I&oc. Zool. Soc. 1834, 



p. 39 -.Trans. Zool. Soc. vol. i. p. 204, pi. 29, f. 5 Mull. 



Syn. Nov. Test. Viv. p. 149. (Crepidula L.) Lam. An. s. Vert. 



vol. vii. p. 649, no. 20. (lanacus L.) H. $ A. Ad. Gen. i 



p. 370, 



