CORBULA. 181 



cose ; the smaller one only marked with a few central and rather 

 remote elevated lines : the larger one simply and closely grooved 

 concentrically, its umbo greatly projecting beyond the other. 

 Anterior extremity rounded ; posterior termination rapidly at- 

 tenuated, and obtusely subbiangulated. Umbonal ridge obsolete. 



Plate IX., figs. 7 to 12, and (animal) Plate G, fig. 3. 



Tellina gibha, Olivi, Zoolog. Adriat. p. 101. 



Mya incequivalvis, Mont. Test. Brit. p. 38, suppl. pi. 26, f. 7. — Linn. Trans. 



vol. viii. p. 40, pi. 1, f. 6. — Turt. Conch. Diction, p. 107. 



— Wood, General Conch, p. 113. — Dillvv. Recent Shells, 



p. 55. — Index Testaceolog. pi. 3, f. 40. 



Corhida nucleus. Lam. Anim. s. Vert. (ed. Desh.) vol. vi. p. 139. — Turt. Dithyra 



Brit. p. 39, pi. 3, f. 8, 9, 10.— Brit. Marine Conch, p. 56.— 



Brown, 111. Conch. G. B. p. 105, pi. 42, f. 7, 8, 9.— Sower- 



BY, Genera Shells, Corbula, f. 1. — Desh. Elem. Conch, pi. 8, 



f. 7, 8, 9.— Phil. Moll. Sicil. vol. i. p. 16, and vol. ii. p. 12. 



— SowERBY, Conch. Manual, f. 89. — Reeve, Conch. Sys- 



temat. pi. 36, f. 1. — Hanl. Recent Shells, p. 46.— Reeve, 



Conch. Iconica, Corbula, pi. 2, f. 10. 



„ striata, Flem. Brit. Anim. p. 425. — Desh. Exp. Scien. Algerie, Moll. 



p. 231. 

 „ olympica, Costa, Test. Sicil. p. 27. ' 



„ inwquivalvis, Macgilliv. Moll. Aberd. p. 303. 

 „ rotundatcc, Sowerby, Min. Conch, pi. 572. 



Encyclopedie Methodique, Vers, pi. 230, f. 4. 



Whilst the naturalist, whose efforts at collecting are con- 

 fined to the rocks, sands, briny pools, and streamlets of our 

 coast, is apt to regard the species under consideration as of 

 unfrequent occurrence, its extreme prevalence is a subject 

 of almost petulant complaint from the habitual dredger. 



The shape of this Corbula is more or less triangular, and 

 its texture very solid and opaque. The valves are remark- 

 ably unequal ; the right, or larger one, not merely over- 

 lapping the other at the base, and exceeding it, ventricose 

 as it is, in profundity, but projecting beyond it at the um- 

 bones in a most remarkable manner, its broader beak curl- 

 ing over, and resting, as it were, upon the margin of the 

 lesser valve. They are both of them nearly devoid of 



