Lateral Teeth, serrated or divided, 

 Cyrena trigonella Cyrena fuscata 



orientalis fluminea 



cor violacea. 



Lateral Teeth, entire. 



Cyrena depressa Cyrena Bengalensis 



Caroliniensis Zeylanico. 



[One fossil species.] 





» 



r 



GALATHEA. 



VENUS PARADOXA. 



Sowerbys Genera, No. 3, pi. 1. 

 This elegant shell inhabits fresh water rivers, and in 

 some respects is nearly allied to the Cyrense, from 

 which however the divergent form of its primary tooth 

 distinguishes it. Shell equivalve, subtriangular, pri- 

 mary teeth furrowed, two on the right valve joined at 

 the base, three on the other valve, placed triangular- 

 ly, the intermediate one being advanced, separate, 

 thick, and callous; the muscular impressions are late- 

 ral, and appear double on each side; shell covered 



