112 CARDIUM. 



Lister Conch, t. 320. f. 157. Argenville, t. 23. f. D. Eric. 

 Meth. t. 294. f. 2. 



Inhabits the coasts of the Nicobar Islands. Chemnitz. The 

 Gulf of Bengal. Bruguiere. 



Shell about fourteen lines long, eleven broad, and six high ; it 

 may be distinguished from C. Cardissa by its plain or only 

 very minutely crenulated keel, and from C. humanum by its 

 being narrower in proportion to the length ; and from both, 

 by its anterior side, which is remarkably concave, except to- 

 wards the hinge, where it becomes slightly elevated. 



monstrosum. 6. Shell heart-shaped ; valves com- 

 pressed, with the front margins incurved, and 

 the anterior side very concave ; keel slightly 

 toothed, and the umbones approximated. 



Cardium monstrosum. Chemnitz, vi. p. 155. t. 14. f. 149 



and 150. Gmelin, p. 3253. 

 Cardium Cardissa Var. D. Bruguiere Erie. Meth. p. 209. 

 Cardium, No. 2. Schroeter Einleitung, iii. p. 52. 

 Eric. Method, t. 295. f. 1 . 



Inhabits the coasts of the Nicobar Islands. Chemnitz. New 

 Zealand. Bruguiere. 



Shell about an inch and a quarter long, and the length and 

 breadth are nearly equal ; it differs from the three foregoing 

 species, in having one side convex and the other very concave, 

 and their lower extremities curved upwards towards the 

 hinge ; it has moreover the concentric grooves on the convex 

 side more numerous, and is marked on a white ground with 

 yellowish chevrons towards the keel. 



retusum. 7. Shell heart-shaped, valves slightly 

 keeled, and marked with crenulated longitu- 

 dinal grooves, and a crescent-shaped cavity 

 beneath the umbones. 



Cardium retusum. Linnceus Sj/st. Nat. p. 1121. Bom. 



Mus. p. 41. t. 3. f. 1 and 2. Chemnitz, vi. p. 147. t. 12. 



f. 139 to 142. Schroeter Einl. iii. p. 30. Gmelin, p. 



3245. Bruguiere Enc. Method, p. 210. Wood's Conch. 



p. 243. t. 58. f. 4 and 5. 

 Cardium auricula. Forsk. Fauna. Arab. p. 122. Gmelin, 



p. 3253. Wood's Conch, p. 229- 

 Regenfuss, ii. t. 9. f- 20. Eric. Method, t. 249- f. 3. 

 Inhabits the coasts of Arabia and Egypt. Forskahl. Tranque- 

 bar. Chemnitz. Persian Gulf and Red Sea. Bruguiere. 

 China. Humphreys. 



