BIVALVES MY A. 



17 



Division II. — Hinpe callous, icithout teeth. 



Scientific N'atne. Locality. Common Xante, 



Edcnhila Caspian Sea Toothless Gaper • 



Membranacea • • • Iceland Membraneous G. 



Nor%%cgica Norway Norwegian do • • 



Siliqua N. America Bean-pixl • • do ■ 



Division III. — Hinge with teeth ivserted into the opposite 

 valve. 



The M.ponderosa, or M. crassa of some authors, with 

 others in this division, are remarkable for their exces- 

 sive weight and thickness ; which is universally the 

 case with those that are found in rapid rivers and 

 cataracts. 



The M, margaritifera is famous for tJie production 

 of fine pearls, and was formerly found in great quan- 

 tities in the river Conway in Wales, and in Scotland. 



Scientijic Xame. Locality. Common A^ame. 



Batava Dauube,Rivers of Holland 



R. Kenuet Dutch Gaper 



Pictorum European Rivers Painters'- • . do 



Ovata Rivers of England • Oval do 



Radiata Ri^ ers of Malabar Radiated • • do 



Ponderosa Chinese Rivers Ponderous • do 



Complanata •••• North American Rivers- • Smooth do 



Nodulosa Rivers of North Europe- • Knotted • - • do 



Margaritifera Rivers of Coromandel - • • Pearl do 



Corrugata Ditto Wrinkled-.do 



Rugosa Ditto Rongli ... do 



Variabilis South American Rivers- • \'ariablc - • do 



r 



