154 TESTACEOUS MOLLUSCA. 
A Cyuinprica. W. S. t. 2. f. 3.  Transversely elongated, 
very inequilateral, margins subparallel, scarcely at all sinuated. 
13..23.—Mediterranean.— West Indies. With age the length 
increases more on the anterior than the posterior side, and the 
hinge consequently is nearer the centre in the young than in older 
specimens. 
A. Fusca. Brug.—lLam. 14.—A. Bicotorata. W. t. 9. 
. 11. A. Barpatra. Var. B. Gmel. 3307.—D. p. 231.— 
List. t. 231. f. 65.—Ch. f. 534.—E. t. 308. f. 5. Oblong, 
rounded at both ends though slightly angulated anteriorly, de- 
pressed, covered with a woolly brown epidermis, reddish chocolate 
with a white ray extending from the depressed and whitish um- 
bones a little way down the anterior slope, with numerous fine 
longitudinal granulated ribs and delicate transverse striz; the 
margin all but closed. 13.—West Indies.—Beside the crenu- 
lations of the hinge, finer ones line the posterior and anterior 
MATGINS. * 
A. Macgetuanica. Gimel. 3311.—D. p. 229.—Lam. 15.— 
Ch. f. 539.—E. t. 309. f. 4.—W. t. 9. f£ 9. Transversely 
oblong, curved, contracted in the middle of the margin, posterior 
side the shorter and narrower, white or slightly ferruginous under 
a dark brown somewhat bearded epidermis; decussated by striz, 
the umbones approximated and the margin gaping. 21.—<Straits 
of Magellan. 
A. Lacrea.* Jin. 1141.—D. p. 236.—Lam. 17.—List. t. 
235. f. 69.—Pen. 4. t. 58. f. 59.—W. t. 9. f. 24. Oblong, 
subequilateral, rounded posteriorly, angular anteriorly, white with 
a brown velvety epidermis and crowded longitudinal grooves, 
merely crossed by the wrinkles of growth; area between the beaks 
very sunken; white within. }..3.—Hurope. 
A. Pistacuta. Lam. 19. Ovate, grey, with decussated striz, 
the beaks approximated and the valves internally striated and dark 
brown. 2.—TZimor and South Seas. Smaller but scarcely dif- 
fering from A. Fusca. 
A. Pisotina. Lam. 20. Very small, obovate, ventricose, 
decussated by strize of which the longitudinal ones are the more 
prominent ; beaks approximated, pearly within. 4.—New Hol- 
land. Not unlike Lactea in shape. 
A, Cancetiarta. Lam. 21. Oval, quadrangular, violet 
brown within and without, with longitudinal granular furrows and 
transverse strie; beaks approximated. 3.—Closely resembling 
Lactea in shape but more inequilateral and has some affinity also 
to Pisolina. 
A. Cauuirera. Lam. 22. Oval oblong, rounded at each 
extremity, violet brown, with longitudinal transversely striated 
