VENUS. 191 



Inhabits the coasts of the West Indian Islands, burrowed in 

 coral and stones. Chemnitz. 



Shell about an inch and a quarter both in length and breadth ; 

 white, and protuberant at the umbones. According to La- 

 marck's description it gapes at both ends, and has two teeth 

 in one valve, and a bifid tooth in the other. It has the car- 

 tilage external, and belongs to the same natural family as 

 Donax Irus. 



divergens. 74. Shell somewhat heart-shaped, with 

 minute, crowded, parallel, regularly zic-zac 

 transverse strise. 



Venus divergens. Gmelin, p. 3269. 

 Venus divaricata. Chemnitz, x. p. 357. t. 172. f. 1666 

 and J 667- 



Burrows in coral on the coasts of the West India Islands. 

 Chemnitz. 



This shell in its size and form resembles V. lapicida, but dif- 

 fers in being marked with minute crowded strise, which form 

 regular parallel chevrons. 



plumbea. 75. Shell somewhat heart-shaped, thick, 

 ponderous, slightly angulated on one side, 

 and transversely wrinkled about the umbones 

 and margin ; margin slightly crenulated. 



Venus plumbea. Chemnitz, vii. p. 61. t. 69. f. A to D. 



Venus ponderosa. Gmelin, p. 3280. 



Venus, No. 51. Schroeter Einl. iii. p. 173. 



Crassatella gibba. Lamarck Syst. des Anim. p. 119. 



Mactra. Encyclopedie Methodique, t. 259- f. 3. 

 Inhabits the coasts of New Zealand. Chemnitz. 

 Shell about two inches long, and the length and breadth are 



about equal ; colour cinereous ; it is transversely wrinkled 



about the umbones and margin, and the intermediate space 



is glabrous ; the hinge has two teeth with an internal hollow 



for the cartilage above them. 



* ## Sub-orbicular. 



tigerina. 76. Shell sub-orbicular, compressed, 

 with decussated strias; posterior depression 

 minute and excavated ; margin entire. 



