NATURAL SCIENCES OP PHILADELPHIA. 201 



Conchoides, (part,) Breyn., Dissert, p. 8, 1732. Gualtieri, Ind. tab. 105, 1742. 



Solen, (part.) Tournefort, in Gnaltieri Index, 1742. 



Mya (part.) Linn., Westg. Res. p. 187, 1747. Syst. Nat. (ed. 10) p. 670, 1758. 



Chamcepholas, (part.) Browne. 



Concha-Eboracensis, Klein, Ostracol. p. 170, 1753. 



ITypogcea, (part.) Poli, Test. utr. Sicil. i. p. 29, 1791. 



Hypogaoderma, (part.) Poli, Test. utr. Sicil. ii. p. 251, 1795. 



There are but four known recent species of Pholas as now restricted, and. 

 they are very easily distinguishable from each other. 



*Margins of the valves regularly rounded anteriorly P. costata. 



#* Anterior ventral margins emarginate Subgenus Cyrtopleura. 



a. Posterior extremity of the shell not truncate P. crucifera. 



b. Posterior extremity truncate. 



Truncated end but very slightly convex in outline P. truncata. 



Truncated end rounded, shell short and broad P. 1 a t i s s i m a. 



P. costata, Linn., Linnaeus, Syst. Nat. 1111. Adans., Genera iii. t. 89, f. 1, 1, a. 

 Anton. Verzeich der Conch, p. 1. Blainville, Man. de Maiacol. t. 79, 

 f. 6. Born., Testacea, p. 15. Bosc. Hist. Nat. des Coq. ii. p. 195. Brug. 

 Encyc. Meth. t. 169, f. 1,2. Catlow., Conch. Nomenc. p. 3. Chemnitz, 

 Conchyl. Cab. viii. t. 101, f. 863. Chenu, Man. de Conch, ii. f. 1, 2, 3. 

 Deshayes, Encyc. vers. iii. p. 754. Deshayes, Traite Elem. i. pt. ii. t. 

 3, f. 10. Dekay, Mollnsca New York, p. 2*48. Dillwyn, Desc. Cat. p. 

 36. D'Orbigny, Voy. Amer. Merid. Mollusques, p. 496. D'Orbigny, Mol- 

 lusques, Sagra's Cuba, ii. p. 213. Favanne, Conchyl. t. 60, f. 1. 

 Fischer, Journ. Conchyl. 2d ser. iii. p. 48. Gibbes, in Tuomey's Geol. 

 S. Carolina. Gmelin, Syst. Nat. p. 3215. Gould, Invert. Mass. p. 27. 

 Gray, Ann. and Mag. Nat. Hist. 2d ser. viii. p. 381. Gualtieri, Index 

 Test. t. 105, fig. g. Hanley, Desc. Cat. p. 6. Jay, Cat. 4th edit. p. 10. 

 Knorr, Vergniig. ii. t. 25, f. 4. Kurtz, Cat. Shells, N. and S. Carolina, 

 p. 3. Lamarck, Anim. sans Vert. (Desh. Edit.) vi. p. 45. Lister, Conch. 

 t. 434, f. 277. Mawe., Conch, t. 1, f. 4. Menke, Syn. p. 73. Morcb. 

 Cat. p. 3. Potiez and Mich., Gallerie des Moll. ii. p. 269. Reeve, 

 Conch. Syst. t. 23. Schroter, Einleit. Conch, iii. p. 537. Sowerby, 

 Genera No. 23. Sowerby, Monog. Pholas. Thes. Conch, ii. p. 487, t. 

 102, f. 8, 9. Spengler, Skrivt. Nat. ii. p. 86. Stimpson, Shells New 

 England, p. 25. Stimpson, Check List E, Coast Shells, No. 243. Wheat- 

 ley, Cat. Shells. U. S. p. 2. Wood, Gen. Conch, t. 15, f. 1, 2. Wood, 

 Index Test. t. 2, f. 4. Wyatt, Conch, p. 28, t. 3, f. 4. 



Coll. Acad. Nat. Sci., from Georgia, Cuba, Vera Cruz. Coll. Dr. J C. Jay. 

 Coll. G. W. Tryon, Jr., (from Atlantic City, N. J.) Coll. Isaac Lea, LL.D. 



Dr. Gould included this species in his " Invertebrata," on account of the dis- 

 covery by Prof. C. B. Adams of an extensive bed of dead shells in New Bedford 

 harbor. He subsequently announced it as living at this locality, remarking 

 that he was not aware of its existence at any other place north of the Mexican 

 Gulf. (Bost. Proc. ii. p. 81, 1845.) 



Dr. De Kay described P. costata as a Southern shell, and no account of its 

 occurrence north of North Carolina has been noticed, except "New York," in 

 Jay's Catalogue. Dr. Stimpson writes to me that he has never met with this 

 shell at any intermediate locality ; therefore I am glad to announce its occur- 

 rence at Atlantic City, New Jersey, where I obtained several perfect valves on 

 the beach, and at Cape May, New Jersey, where Dr. Leidy has procured a few 

 specimens. 



Subgenus Cyrtopleura, Tryon. 

 Margins of the valves emarginate anteriorly ', making a short wide hiatus. 

 P. crucifera, Sowerby. 

 1862.] 14 



