158 TESTACEOUS MOLLTJSCA. 



ribs, M^iich are much narrower than tlie interstices, nmbones 

 oblique ; posteriorly, obliquely rounded ventrally, rectangular dor- 

 sally ; emarginated anteriorly : ligamental area narrow and elon- 

 gated anteriorly. If. — Indian Ocean. — 3Iuch resembles lihombea. 



A. Inequivalvis. ]3rug. diet. no. 16. — A. Indica. var. 

 D. p. 235.— Ch. f. 552.— E. t. 305. / 3. «.— A. Imbricata. 

 TF. t. 9.f. 4. Obliquely lieart-sliaped, ventricose, inequivalve, one 

 valve projecting beyond the other anteriorly, and at the I'ounded 

 ventral margin; rather broader than long, anterior edge nearly 

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

 beaks approximate. 2^. — Indian Ocean. 



A. Indica. Gmel. 33\2.—D. p. 234.— Lam. 31.— TF. t. 9. 

 f. 21.— List. t. 232. f. 66.—Cfi. f. 543. Transversely elongated 

 ovate, inequivalve, thin, and whitis^ with many ribs which are 

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

 them. 1..1J. — Sumatra. 



A. Senilis. Lin. 1142.— Z>. p. 234.— Lam. 32.— Ch.f. 5.54. 

 5, Q>.—E. t. 308. /. 1.— TF. t. 9.f. 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.— Z>ia???. 2|. — Africa. 



A. Buasihana. Lam. 33. — IF. 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 

 ai-ea pectinated. 1|^. — Rio Janeiro. 



A. CoRBicuLA. Gmel. 3310. — A. Corbula. D. f. 235. — 

 Lam. 34. — Cli. f. 559. — E. t. 309. /. 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. Larn. 35.— An. Gray, in W. S. i. 2./. 12.^ ^ 

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

 approximated, anterior slope obHque, and imbricated with scales. ^. 

 — New Holland.^ 



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 (fde Deshayes). I add horoever the characters. — A. 

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

 oblong, with decussated striae, reddish brown clouded with pale 



