108 PIIOLADID^. 



. Pholas dactylus, Linnscus. 



Valves beaked : umbonal region crested by a series of subquad- 

 rangular cells: dorsal plates 4 in number.* 



Plate III. 



Pholas dactylus, LiNN. Syst. Nat. ed. 12, p. 1110. — Penn. Br. Zool. ed. 1, 177, 



vol. iv. p. 7G. pi. 39, f. 10.— Da Costa, Br. Conch, p. 244. 



pi. IG, f. 2.— DoNov. Br. Shells, vol. iv, pi. 118— Mont. 



Test. Brit. p. 20 and 528.— Linn. Trans, vol. viii. p. 30. 



Dorset Catal. p. 27, pi. 3, f. 2.— Turt. Conch. Diet. p. 143. 



Dithyr. Brit. p. 8. — Flem. Brit. Anim. p. 457. — Brit. 



Marine Conch, p. 31. — Brown, 111. Conch. G. B. p. 115, pi. 



49, f. 1 , 2, 3.— Born, Mus. Cres. p. 1 4. pi. 1, f. 7.— Chemn. 



Conch. Cab. viii. p. 353, pi. 101, f. 859. — Spengl. Skrivt. 



Naturhist. Selsk. vol. ii. part i, p. 85. — PoLi, Test. Sicil, 



pi. I, f. I to 5. — Wood, General Conch, p. 77, pi. 13. — 



DiLLw. Recent Shells, vol. i. p. 35. — Lam. Anim. s. Vert. 



ed. 2, p. 43. — Maave, Conch, pi. 3, f. 3.— Index Testae, pi. 



2, Phol. f. 1.— Sowerb. Gen. Sh. Pholas. f. 1 .—Reeve, 



Conch. System, pi. 24. — Sow. Conch. Manual, f. 55. — Phii,. 



Moll. Sicil. vol. i. p. 3, and vol. ii. p. 4. — Desh. Exp. Sci. 



Alger. Moll. p. 107, pi. ix. C. E. and G., f. 1, 2, 3 (animal). 

 PhoUis liiuus, Pulten, Dorset, p. 20. 



„ callosa, Cuv, R. Anim. ed. Croch. pi. 113, f. 1. 

 Pholadc dactylc, Chenu, Trait^ Elem. p. 38, f. 111. 

 Lister, Hist. Conch, pi. 433, f. 276. 



This ancient and universally-known species of Pholas is 

 much elongated in shape, rather inflated, not very fragile, 

 dull white, and extremely inequilateral. The entire surface 

 is sculptured by concentric lamellar stria), which, moderately 

 distant posteriorly, become approximated in front, where 

 they form short vaulted spines, arranged in close-set radi- 

 ating rows. The convexity of the valves is simple, that is 

 to say, they are not divided into distinct areas by a 

 radiating furrow, or concavity. The anterior side, which 

 is the more tumid, is very short, and forms a distinct beak, 

 through the large ventral hiatus incurving that margin ; the 

 posterior side is much produced, and tapers to a rounded 



* These diagnoses refer to the British species only. 



