152 



TESTACEOUS MOLLUSCA. 



* Margin entire. 



A. ToRTuosA. Lin. 1140.— Z>. j). 225.— Lam. \.— Ch. 

 f. 524, 5.~E. t. 305. f. l.—W. t. 9./. 1. Parallelepiped, 

 obliquely keeled one valve more so than the other, twisted and 

 almost equally broad throughout, but rather narrower at the 

 posterior end, dirty or reddish white, with radiating strise and the 

 anterior triangular portion strongly wrinkled transversely ; beaks 

 small and recurved. 1 . . 3 — Indian Ocean. 



A. Semitorta. Lam. 2. — Fav. t. 51. /. C. I. — W. S. 

 t. 2. f. 2. Rather twisted, oblong elliptic, dilated, striated, the 

 valves obsoletely carinated and rounded at their extremities ; beaks 

 recurved. 3^.— Van Diemen's Land. 



A. No^ * Lin. 1140.— Z>. p. 226.— iam. 3—Ch.f. 529.— 

 Bl. t. 65. /. 2— Don. t. 158. f. 1, 2.—E. t. 303. /. 1, ^ 

 t. 305. /. 2.— W. t. 9. /. 2. Oblong rhomboidal, with fifty or 

 sixty radiating grooves, the beaks incurved and very remote; 

 whitish with diagonal broad parallel chesnut stripes ; the broad flat 

 space between the beaks with a few distant grooves radiating from 

 each apex ; inside tinged with chesnut, the hinge with more than 

 eighty teeth; the margin entire. 1 . . 2. — Eurojje. The Atlantic. 



A. Navicularis. Briig. E. p. 99.— i>. p. 227.— W. t. 9. 

 f. h.—Ck. f. 533.— E. t. 30S. /. 3. Oblong rhomboidal, pale 

 rufous with broad wavy chesnut diagonal stripes, with not more 

 than thirty coarse radiating ribs which become broader at the sides, 

 and fine intermediate strise : within brownish, crenulated on the 

 sides of the margin and the hinge with not more than seventy 

 teeth. I . . l^.—St. Domingo. 



A. Tetragona. Pali. t. 25. /. 12, 3.~Lam.. A.—E. t. 308. 

 f- 3. — PIdl. p. 57. Oblong, with longitudinal riblike striae, trans- 

 versely striated, anteriorly straight not emarginated and with an acute 

 prominent keel, pale rufous never striped . 1 . — Mediterranean. 



A. Imcricata.* Brug. E. p. 98.— D. p. 226.— A. Um- 

 BONATA. Lam. 5.— A. Fusca. Don. 5. t. 158. f. A.— W. t. 

 9./. 14.— Ch. f. 532.— List. t. 367. /. 207.— '-£;. 305. /. 3. 

 Ovate, posteriorly rounded, anteriorly forming an oblique angle 

 with the hinge margin very ventricose brownish white within and 

 without, with imbricated crowded decussated acute striae : liga- 

 mental area hollow: margin gaping and quite entire. 1. — 

 Jamaica . — Senegal. 



A. Sin data. Lam. 6. Oval, obtuse at each extremity, with 

 decussated striae, obliquely angulated, ventral margin sinuated and 

 gaping. 1-|. — ]Vew Holland. — {Akin to Ilelbingii and prohablij 

 a variety.) 



A. AvELLANA. Lam. 7- Small, ovate, tumid, ventricose, 

 shortened, with decussated striae, beaks arcuated, anterior slope 



