BIVALVrS DON AX. 



sr 



MACTRA. 



Spengleri. 



Plicataria. 



Papyracea. 



Striatula. 



Striata. 



Rotundata. 



Glabrata. 



Nitida. 



Corallina. 



Lactea. 



*Stultorum. 



Craudis. 



*Solida. 



*Lutraiia [Lavfje 31.] 



Cygiius. 



Maculata. 



Turgida. 



Violacea. 



Cuiieata. 



Glanca. 



Pellucida. 



Fragilis. 



Rugosa. 



Nicobarica. 



Complanata. 



•Listen. 



Piperita. 



DONAX. — \\'edge-siiell. 



Aninud — a Tethj/s : Shell bivalve, with fjeneralhf acrenn- 

 late margin, the frontal margin is verg obtuse; hinge 

 with two teeth, and a single marginal one placed a little 

 hehindy rarely double or triple. 



The most leading characteristic of the Donax is derived 

 from its fomi, which (througliout the nineteen species^ is 

 similar to that of a wedge, being very bro-'d and thick at 

 one extremity, and gradually narrowing and lessening to 



