21 



Scientific name. 



Batava, 



Pictorum, 



Ovata, 



Radiata, 



Ponderosa, 



Complanata, 



Nodulosa, 



Margaritifera, 



Corrugata, 



Locality, 

 Danube,R.of Holland, 

 European Rivers, 

 Rivers of England, 

 " of Malabar, 

 Chinese Rivers, 

 N. American Rivers, 

 Riv. of N. of Europe, 

 Riv. of Coromandel, 



Scientific name. 



Rugosus, 



Variabilis, 



Nodosa, 



Symatophora, 



Suborbicularis, 



Inrequivalvis, 



Labiata, 



Aurita, 



Locality. 

 Riv. of Coromandel, 

 S. American Rivers, 

 Rivers of India, 



" " Guinea, 

 Coasts of Devonshire, 



" British, 



S. American Rivers, 

 Ganges. 



DIVISION IV. 



Hinge toothless, with a conical 

 reception of the cartilage. 



rounded hollow for the 



Vulsella, 



Amboyna, Tranquebar. 



