CORBULA. 185 



from seven to eighty fathoms (E. F.). To its capacity for 

 enduring many conditions of depth is doubtless due its long 

 range in time, for it has inhabited our area ever since the 

 epoch of the coralline crag. 



C. ROSEA, Brown. 



Subtriangularly oval, subequilateral, but moderately ventri- 

 cose, glossy, fulvous (when adult), with a short dark roseate 

 streak on each valve, which diverges widely on either side of the 

 umbones, but does not reach to the margin. Valves not peculiarly 

 unequal, the umbo of the larger and slightly more convex one 

 not projecting greatly beyond the other ; smaller valve almost 

 smooth ; larger valve simply but closely grooved concentrically, 

 the sulci only apparent in the adult towards the margins. Ex- 

 tremities attenuated, the front one rounded, the hinder one most 

 obtusely and subbiangulately pointed. Dorsal slopes moderate, 

 the anterior one nearly straight, the posterior slightly retuse : 

 ventral margin convex or subarcuated. Umbonal ridge obsolete. 



Plate IX. figs. 13, 14. 



Corlula rosea. Brown, 111. Conch. G. B. p. 105, pi. 42, f. 6. — Hanl. Recent 

 Shells, supp. pi. 12, f. .33. — Loven, Moll. Sueciae, p. 49 (from 

 specimen). 



It is with considerable hesitation that we admit this 

 distinct species of Corhula into our Fauna : we wish it to 

 be regarded, then, as only provisionally included until 

 either clearer proofs of its positive indigenonsness, or of the 

 greater probability of its being solely exotic, are afforded, 

 than our own inquiries have been able to eliminate. The 

 original specimens upon which the name rosea was be- 

 stowed belonged to Dr. Leach, and are stated to have been 

 dredged at Falmouth : numerous others were in the cabi- 

 net of the late Mrs. Loscombe, mixed with nucleus. Those 



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