64 LUCINIDiE. 



valve is furnislied, besides having primary teeth, with a strong 

 and not very distant lateral lamina in front, and a smaller less 

 distinct and more remote one behind, both of which fit into cor- 

 responding receptacles in the left valve. The front muscular im- 

 pression is extremely long, and runs almost parallel to the per- 

 fectly simple palleal scar. The diameter of rather a large exam- 

 ple was seven-eighths of an inch. 



A West Indian shell, introduced hy Montagu as found on the 

 shore near Dunbar hy Mr. Lashey. The L. imbricatula of Adams 

 (Jamaica Shells) is very closely allied, but quite distinct, and 

 differs in having a coarser decussation of sublimate scale-like pro- 

 tuberances upon its ribs, which latter become smaller, and not at all 

 divergent, but bent contrariwise, near the hinder termination. 



L. TiGERiNA, Linnaeus. 



Vemis tigerina, Linn. Syst. Nat. ed. 12, p. 1134. — Pulteney, Hutchins, Hist. 



Dorset, p. 34. — Mont. Test. Brit. p. 119, pi. 4, f. 1. — Linn, 



Trans, vol. viii. p. 86, pi. 2, f. 5, (badlj-). — Dorset Catalog. 



p. 35, pi. 1, f. 14.— TuRT. Conch. Diction, p. 240.— Chemn. 



Conch. Cab. vol. vii. pi. 37, f. 390, 391. 

 Lucina tigerina. Lam. Anim. s. Vert. (ed. Dash.) vol. vi. p. 319, (not vars.) — 



Brit. Marine Conch, p. 76. — Desk. Elem. Conch, pi. 16, 



f. 4, 5.— Hanl. Recent Shells, p. 78. 

 Cytherea tigerina, Turt. Dithyra Brit. p. 164, pi. 10, f. 12. — Flem. Brit. Anim. 



p. 445. 

 EncycIop6die Methodique, Vers. pi. 277, f. 4. 



A West Indian shell, introduced by Dr. Pulteney as taken at 

 Weymouth, Studland, and Poole. 



DIPLODONTA, Bronn. 



Shell equi valve, more or less suborbicular, inequi- 

 lateral, nearly smooth, or marked by lines of growth. 

 Hinge composed of two primary teeth (one of which is 

 bifid) in each valve ; no lateral teeth. Ligament external. 

 No lunule. Muscular scars nearly equal, ovate ; pallial 

 impression single. 



Animal shaped as the shell ; mantle open in front, 



