150 TESTACEOUS MOLLUSCA. 



truncated and carinated with its slope more or less concave : teeth 

 and anterior end often tinged with purple internally : anterior dorsal 

 edge rather incurved. — Variety. C. Rostrata. Lam. 3. With 

 the anterior side produced attenuated and slightly beaked. If. — 

 Neiv Holland. 



C. CoRALLioPHAGA. La77i. 4. — Bl. t. 76. f. 3.— Chama C. 

 Gmel. 3305. -Z>. p. 220. — W. t. 9. /. 17.— CA. /. 1673, 4. 

 Oblong, rounded at both extremities, cylindraceous, thin, white 

 tipped with purple at the beaks, diaphonous, compressed anteriorly ; 

 marked with decussated strise which at the margin are raised into 

 low ridges. 2. — In 3fadrepores at St. Domingo. (Bears some 

 7'eseniblance to Mytilus Lithophagus.) 



HIATELLA. 



Eqaivalve, very inequilateral and transverse ; gaping at the ventral 

 margin ; hinge with a small tooth in the right valve ; and two 

 oblique somemhat larger 07ies in the left valve; ligament 

 external. 



H. Arctica.* Lam.— Turt. Biv. t. 2./. 12.— Solen Minu- 

 Tus. Lin. 1115.— TF. t. 3. /. 33.— i>. p. 69.— Hunt. t. 1. /.4. 

 — Ch.f. 51, 2.— Saxicava A. Phil. t.3.f.3. Oblong, produced 

 and truncated anteriorly, white with transverse wrinkles, ligamental 

 edge subincurved, anterior slope with two oblique ridges usually 

 armed with spines. — Variety. Without the spines. (H. Ob- 

 LONGA. Tiirt. Biv. t. 2. /. 13.) f . — Atlantic and 31editer- 

 ranean.^ 



ISOCARDIA. 



Equivalve, heart-shaped, ventricose ; beahs distant, divergent, and 

 spirally turned to one side ; hinge raith two primary flattened 

 teeth, one of them recurved and under the beak ; an elongated 

 lateral one under the ligament which is external and forhed on 

 one side. 

 I. Cor.* Lam. \.—Bl. t. 69. /. 2.— Chama Cor. Lin. 



\137.—D. p. 212.— Ch. f. 483.— E. t. 232. f. \.—Don. 4. 



t. 134. — W. t. 9. y. 1. Heart-shaped, globose, smooth, fulvous 



and the beaks clouded with white; epidermis reddish. 3..2f. — 



Europe. 



I. MoLTKiANA. Lam. 3.— Chama M. B. p. 213.— Ch. 



f. 484, 5, 6, 7.—E. t. 233. /. 1,— Cardita M. Brug. Die. 



p. 404. Heart-shaped, subtriangular, inequilateral, yellowish white. 



' Compare Mytilus Pracisus of Montagu, t. 4. f. 2. — (W. 

 t. 12./. IL) 



