P H L A S. 



Species 10. (Fig. a, Ik Mus. Brit.) 



Phol.vs cuuta. Pho. teMd pared, fusco-viru/escenti, 

 pyriformi, clausd, tetmi, canali angusto medio coii- 

 strictd, antice tenuiler slriatd, vix echinatd, margine 

 ventrali globoso, valvuld dorsali oblongo-kexugond ; 

 antice Icevigatd, acuniinatd. 



The short Pholas. Sliell small, greenish-brown, 

 closed, thin, constricted in tlie middle by a narrow 

 canal, finely striated anteriorly, scarcely echinated, 

 with ventral margin globose, dorsal valve ot)long, 

 hexagonal ; anteriorly smooth, acuminated. 



SowEREY. Proc. Zool. Soc, 18."34. 



Hab. West Columbia. In soft stone at low water. A' 

 small shell, with one cutaneous plate covering the 

 umboes, and thoroughly enclosed when full grown. 



Species 17. (Fig. fi,h.) 



Pholas latissima. Pho. tedd subcomj)res»d, laid, sub- 

 quadratd, late utrinque apertd, postice late trun- 

 catd, antice svbacuminald, costellis concenlricis, 

 costisque noduli/eiis decussatd ; umbonihus fuh- 

 centralibus, marginibus dorsalibus re/lexis. 



The v-ert wide Pholas. Shell subcompresseu, broad, 

 subquadrate, widely open on both sides, widely 

 truncated posteriorly ; anteriorly subacuminated, 

 decussated with concentric ridges and radiating 

 nodulose ribs ; umboes subcentral, dorsal margins 

 reflected. 



SowERBY. Proc. Zool. Soc, 1.S49. 



Hab. Manilla Bay. Taken by Mr. Cuming. This 

 species appears to have no accessory valves. 



Species 18. (Mus. Cuming in Brit.) 

 Pholas Calikounica. Pho. testd mngiid, ivntricosd, 

 subcylindricd, in partes tres oh/ique divisd ; parte 



anticd prope niarginetn ventralem sublmvigatd^ 

 dorso usque ad medium imbricalim costato ; parte 

 medid pland, epidermide crasnd, indiitd ; parte 

 posticd oblique triangulari, transverse epidermide 

 laminald, ad terminum truncatd ; margine ventraJi 

 integumento divLw, elongato, corneo, ccelato ; mar- 

 gine dorsali integumento Iriplicato, elongato, ad 

 umbones angustato ccelato. 

 The Califoknian Pholas. Shell large, ventricose, 

 subcylindrical, obli(juely divided into three parts ; 

 anterior part rather smooth near the ventral 

 margin ; from the back to the middle with imbri- 

 cated ribs ; middle part smooth covered with a 

 thick epidermis; posterior part obliquely tri- 

 angular, transversely laminated with an epidermis, 

 truncated at the end ; ventral margin hidden by a 

 divided, elongated, horny integument; dorsal 

 margin hidden by a triplicate, elongated integu- 

 ment, narrow at the umboes. 

 CoSRAD. Ann. Nat. Sci. Phil., vol. i. p. 2;3G, t. 18, f 4 

 Hab. Monte Rey, California, in sandstone under deep 

 water. M. Hartweg. The largest and one of the 

 most curious of the enclosed species. 



Species 19. (Mus. Cuming in Brit.) 



Pholas acuminata. P/to. testd clausd, subpyriformi, 

 ventricosd, in partes tres oblique divisd ; itarte an- 

 ticd rotundd, versus marginem dorsaleni minute 

 radiatim scabrd ; parte medid late plana, epider- 

 mide crassd indutd ; parte posticd acute angulatd, 

 attenuatd ; marginibus doi-salibus veritralibusque 

 integumentibus plicatis ccelatis ; valvuld dorsali 

 unicd mag7id, subquadratd. 



The .acuminated Pholas. Shell closed, subpyriform, 

 ventricose, obliquely divided into three parts ; 

 anterior part rounded, radiately scabrous towards 

 the dorsal margin; middle part broadly Hat, covered 



