TRIBE CONCHACEA. 109 



C. Lunularis. 1 Lam. 74. — Del. t. 9. f. 0. Sub-orbicular 

 heart-shaped, longer than broad, transversely grooved, livid, rayed 

 towards the margin : the lunule with a white triangular spot at its 

 base: inside white. 1^. — America? 



C. Cygnus. Lam. 77. Heart-shaped, tumid, uniform white 

 within and without, with raised transverse striae which become 

 smaller towards the margin ; the beaks inclining towards the 

 heart-shaped lunule. li. — Mediterranean. 



C. Dentaria. Lam. 78. Triangular broadly, transverse, pale 

 fulvous with white rays, and the anterior side with a reddish-brown 

 spot more apparent in the interior. 2\. — Rio Janeiro. 



C. Effossa. Nobis, in Z. P. 1842.. Oval, sub-cordiform, sub- 

 equilateral, thick, glossy, convex, with strong rather distant trans- 

 verse grooves, the intervening spaces flattened, pale livid variegated 

 by darker zigzag veins ; lunule impressed and lanceolate : lozenge 

 deeply excavated, the sides smooth, white with wavy transverse ches- 

 nut bands : inner disc stained with purple ; inner margin distinctly 

 crenated. 4. . . i£. 



C. Excavata. Nobis in Z. P. 1842. Rounded ovate, sub- 

 equilateral, posteriorly expanded, anteriorly narrowed by the much 

 arcuated ventral margin sweeping obliquely upward to meet the 

 posterior edge ; thick, smooth, glossy, pale fulvous, more or less 

 distinctly marbled with livid angular markings : lunule lanceolate : 

 lozenge very deeply excavated, the sides flattened, white with a few 

 livid veins : inner disc with a pale crimson stain, inner margin 

 finely crenulated. 1 . . 1-J. 



C. Solandrt. Gray in Ann. Phil.— C. Hvans. JV. 8. t. 2. 

 f. 1 1 . Elliptical-sub-cordiform, thick, very convex, sub-equilateral, 

 smooth, polished, white with angular clouded livid purple markings, 

 especially near the umbones : lunule and lozenge lanceolate, the 

 former indistinct, the latter excavated : margin crenulated. 1^. . \\„ 

 — China. — Ahin with the two 'preceding to Donax Scrota. 



VENUS. 



Equivalve, inequilateral, transverse, or sub-orbicular ; hinge with 

 three teeth in both valves, all approximate, the lateral ones 

 divergent at their summits ; ligament external, concealing the 

 lozenge. 



* Inner margin crenulated or toothed. 



Section A. — With lamellar stria?. 



V- Puerpera. Lin. Mantissa, p. 545. — Lam. 1. {excluding 

 var.2.)—D.p. 188.— Ch. f. 388, 9.—E. t. 278./ I.— Reeve. 



1 C. Flexuosa. Lam. 72. — Macrodon. 73. — Squamosa. 75, 

 and Cardilla, 76, belong to Venus. 



