226 ARCA. 



Red Sea. Forskael. China, and the Nicobar Islands. Hum" 

 phreys. 

 Shell about an inch or fourteen lines long, and thrice as broad, 

 obliquely keeled and twisted,, and almost equally broad 

 throughout, but rather narrower at the posterior end ; the 

 colour is dirty or reddish white ; both valves are marked 

 with decussated stria?, and the part separated by the keel at 

 the anterior end of the larger valve is strongly wrinkled trans- 

 versely. Pennant mistook A. Noce for this species, and Lin- 

 naeus says, that A. tortuosa has been found of a smaller size 

 on the coasts of Norway, which may probably have origi- 

 nated in some similar mistake. 



no.e. 2. Shell oblong-rhomboidal, strongly striated 

 longitudinally, with the apices incurved and 

 very remote ; margin entire and gaping. 



Area Noae. Linnecus Si/st. Nat. p. 1 140. Born Mus. p. 



88, and Vign. at p. 86. f. b. Chemnitz, vii. p. 177- t. 



53. f. 529 to 531. Schroeter Einl. iii. p. 260. Gmelin, 



p. 3306. Montagu Test. p. 139. Donovan, v. t. 158. 



f. 1 and 2. Maton and Racket, in Lin. Trans, viii. p. 



91. Bruguiere Enc. Meth. p. 97. Lamarck Sj/st. des 



Anim. p. J 16. 

 Area tortuosa. Pennant Zool. iv. p. 97- 

 Bonanni Rec. 2. f. 32, and Kirch, f. 31. Lister Conch. 



t. 368. f. 208. Rumphius, t. 44. f. P. Petiver Amb. 



t. 17. f. 10. Gualter, t. 87- f. H. Argenville, t. 23. f. 



G. Knorr, i. t. 16. f . 1 and 2. Regenfuss, i. t. 12. f. 



73. Favanne, t. 51. f. D 4. Enc. Meth. t. 305. f. 2. 

 Inhabits the Red Sea, Mediterranean, and Indian Ocean. 

 Linn ecus. Coasts of Barbadoes. Lister. Amboyna. Rum- 

 phius. Antilles. Regenfuss. Bay of Naples. Ulysses. Bri- 

 tain. Pennant, fyc. Glamorganshire. L. W. D. 

 Shell about an inch long towards the anterior end, but is shorter 

 at the hinge, and the breadth is about two inches ; the co- 

 lour is white, with diagonal parallel zic-zac chestnut stripes, 

 and the margin is dark brown ; the broad fiat space between 

 the apices has a few distant grooves radiating from the umbo 

 in each valve. 



1MBRICATA. 3. Shell ovate-rhomboidal, with de- 

 cussated striae, of which the transverse are 

 imbricated and acute; apices incurved and 

 very remote ; margin entire. 



