154 TESTACEOUS MOLLUSCA. 



A Cylindrica. W. S. t. 2. f. 3. Transversely elongated, 

 very inequilateral, margins subparallel, scarcely at all sinuated. 

 l|..2f. — 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. — Lam. 14. — A. Bicolorata. W. t. 9. 

 / 11. A. Barbata. Var. B. Gtnel. 3307.— D. p. 231.— 

 List. t. 231. /. 65.— Ch. f. 534.— E. t. 308. /. 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 striae ; the 

 margin all but closed. 1J. — West Indies. — Beside the crenu- 

 lations of the Jmige, finer ones line the posterior and anterior 

 margins. 



A. Magellanica. Gmel. 3311. — D. p. 229. — Lam. 15. — 

 Ch. f. 539— -#. t. 309. /. 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 striae, 

 the umbones approximated and the margin gaping. 2^ — Straits 

 of Magellan. 



A. Lactea.* Lin. 1141. — D. p. 236. — Lam. 17.— List. t. 

 235. / 69.— Pen. 4. *, 58. /. 59.— W. t. 9. /. 24. Oblong, 

 sub equilateral, 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. J . . f . — Europe. 



A. Pistachia. Lam. 19. Ovate, grey, with decussated striae, 

 the beaks approximated and the valves internally striated and dark 

 brown, f . — Timor and South Seas. Smaller but scarcely dif- 

 fering from A. Fusca. 



A. Pisolina. Lam. 20. Very small, obovate, ventricose, 

 decussated by striae of which the longitudinal ones are the more 

 prominent ; beaks approximated, pearly within. %.< — New Hol- 

 land. Not unlike Lactea in shape. 



A. Cancellaria. Lam. 21. Oval, quadrangular, violet 

 brown within and without, with longitudinal granular furrows and 

 transverse striae; beaks approximated. |-. — Closely resembling 

 Lactea in shape but more inequilateral and has some affinity also 

 to Pisolina. 



A. CalliferA. Lam. 22. Oval oblong, rounded at each 

 extremity, violet brown, with longitudinal transversely striated 



