TRIBE. CORBULACEA. 



Inequivalve ; ligament internal; one of the beaks 

 always projecting beyond the other. 



GENUS. COREULA. 



Regular, equivalve, inequilateral ; with a conical, bent, 

 ascending, primary tooth in each valve, a small pit 

 at its side ; destitute of lateral teeth; ligament ex- 

 ternal. 



C. NUCLEUS. Lam. 6. Turt. B. p. 39. t. 3./. 8 to 

 10. Sow. G. f. I. Reeve, t. 36. /. ].. MYA INE- 

 QUIVALVIS. Mont. p. 38. t. 26./ 7. Pen. 4. p. 126. 

 Lin. T.S.p. 10. t. I./. Q. Wood. G.C.p. 113. 

 D.p. 55. Turt. C. J). p. 107- E. M. t. 230. /. 

 4. Subtriangular, strong, opaque, generally covered 

 with a brown skin under which it is whitish or flesh 

 color, larger valve convex, regularly striated trans- 

 versely, inclosing the lesser valve over which the beak 

 projects and curves inwards; lesser valve flattish, with 

 a few longitudinal raised striee ; inside smooth, polished 

 round the margin. ....!-. Torbay,fyc. 



GENUS. SPH^ENIA. TURTON. 

 Transverse, inequivalve, inequilateral, open at the an- 

 terior side ; hinge of the left valve with an elevated 

 transversely dilated tooth, of the right valve with a 



