158 TESTACEOUS MOLLUSCA. 



ribs, which are much narrower than the interstices, umbones 

 oblique ; posteriorly, obliquely rounded ventrally, rectangular dor- 

 sally; emarginated anteriorly: ligamental area narrow and elon- 

 gated anteriorly. If. — Indian Ocean. — Much resembles Rhombea. 



A. Inequivalvis. Brug. diet. no. 16. — A. Indica. var. 

 D.j). 235.— Ch. f. 552.— E. t. 305. /. 3. a.— A. Imbricata. 

 W. t. 9.f. 4. Obliquely heart-shaped, ventricose, inequivalve, one 

 valve projecting beyond the other anteriorly, and at the rounded 

 ventral margin; rather broader than long, anterior edge nearly 

 direct, white, thin, with many nearly smooth and flattened ribs, 

 beaks approximate. 2J- . — Indian Ocean. 



A. Indica. Gmel. 3312.— D. p. 234.— Lam. 31.— IT. t. 9. 



f. 21.— List. t. 232. /. 66.— Ch. f 543. Transversely elongated 



ovate, inequivalve, thin, and whitish ; with many ribs which are 



grooved in the middle, the beaks approximated and no area between 



them. 1. . If. — Sumatra. 



A. Senilis. Lin. 1142.— D. p. 234.— Lam. 32.— Ch.f. 554. 

 5, 6.—E. t. 308. /. 1.— IF. t. 9./. 20. Obliquely heart-shaped, 

 nearly as long as broad, tumid, thick, ponderous, white covered with 

 a greenish brown epidermis, with about twelve broad very large 

 unarmed ribs, of which seven or eight are much larger than the 

 rest ; umbones large, obliquely recurved, and distant : within white 

 and polished.— Diam. 2 j. — Africa. 



A. Buasiliana. Lam. 33. — W. S.t. 2.f. 7. — A. Inequival- 

 vis. Sow. Gen. f. 3. Inequivalve, heart-shaped, tumid, anteriorly 

 subangulated, reddish white, with many flattened ribs which at the 

 posterior side are crenulated, at the anterior unarmed: ligamental 

 area pectinated. 1^. — Rio Janeiro. 



A. Corbicula. Gmel. 3310. — A. Corbula. D. p. 235. — 

 Lam. 34. — Ch. f. 559. — E. t. 309. f. 5. Ovate, subtrapeziform, 

 the hinge margin nearly straight, and the rest of the margin 

 rounded, white with radiating transversely striated ribs: beaks 

 obtuse and approximated, the intervening area very narrow. f..l. 

 Cape of Good Hope. 



A. Squamosa. Lam. 35. — An. Gray, in W. S. t. 2.f. 12 7 1 

 Ovate wedge-shaped, with cancellated striae, beaks tumid and 

 approximated, anterior slope oblique, and imbricated with scales. J. 

 — New Holland. 2 



1 The shell from which this figure is taken, is again named by 

 Mr. Gray in the British Museum A. Reticulata var. Are we to 

 understood that these are synonymous ? 



2 Of this species, A. Domingensis, Lam. 16. is at most a 

 variety (fide Deshayes). I add however the characters. — A. 

 Domingensis. Lam. 16. — List. t. 233. f. 67. Transversely 

 oblong, with decussated striae, reddish brown clouded with pale 



