88 TESTACEOUS MOLLUSCA. 



C. Incrassata. Desk, in Lam. 7. p. 257. Solid, triangular, 

 sub-cordiform, inflated ; chesnut brown, quite smooth except at the 

 beaks, which have transverse wrinkles ; slightly inflexed on one side ; 

 margin usually denticulated ; hinge with two strong teeth, one in 

 the right valve minute. — Mediterranean? 



C. Castanea. Say. Am. t. 1. f. 1. — Gould. Mas. — Venus. 

 C. Say. I. A. N. S. Rounded, depressed, solid, and irre- 

 gularly striated, with a chesnut cuticle and acute beaks ; lunule 

 oval-oblong and depressed : within white, with the margins finely 

 crenulated, and the teeth of one valve unequal. 1. — New Jersey. 



C. Borealis. Gray. Ann. Phil. 25. — Venus B. Lin. 1134.? 

 — D. p. 198. — Ch.f. 412, 3, 4. Rounded ovate, both slopes sub- 

 truncated, flattish, transversely striated, white under a reddish 

 brown cuticle, always decorticated at the beaks. 1 ., 1^. — N. 

 Europe ? 



C. Montagui. Gray. Ann. Phil. 25. — Venus Compressa. 

 Mont. t. 26. f. \.—D. p. 167— W. t. 7. f. 19.— Cyprina. C. 

 Turt. Biv. t. 1 \.f. 20. to 23. Sub- triangular, posteriorly rounded, 

 anteriorly but slightly so, obsoletely and irregularly grooved trans- 

 versely, white under a brown cuticle : the depression in front of 

 the beaks, which are very prominent and inclining, sudden. \. 

 — Scotland. 



C. Crenata, — Nicania. C. Gray in Parry Sup. Oval- 

 elliptical, with regular concentric furrows, pale yellowish greeen : 

 umbones sub-central, lunule oblong lanceolate : in one valve a bifid 

 cardinal tooth, in the other two simple ones, two rudimentary small 

 lateral laminae in each : margin crenated. — N. Pole. 



C. Lactea. — Astarte. L. Brod. and Sow. Z. J. 4. — Beechey. 

 Zool. t. 44. f. 12. — Gould. Mas. p. 81. Obovate, compressed, 

 posteriorly shorter, the anterior dorsal margin depressed : dull, 

 with a thick dark cuticle, distinctly marked with concentric lines of 

 growth : inside white, margins quite entire. l£..l-£. — Icy Cape. 

 C. Artica. Gray, in Parry Sup. Roundish ovate, convex, 

 white under a black shining finely concentrically striated cuticle : 

 umbones rather prominent, slightly grooved concentrically ; lunule 

 oblong-ovate, deep, anteriorly lanceolate : in one valve a strong 

 simple cardinal tooth, two diverging ones in the other, lateral 

 laminae two in each valve, the anterior remote and small : edge 

 entire. \\..\\.—N. Pole. 1 



1 Compare with these the Astarte Cyprinoides of Duval, in 

 Rev. Z. Cuv. 1841. 



