Amphidesma variegata 



donacilla 



lactea 



cornea 



albella 



lucinalis 



Boysii 



tenuis 



50 



Amphidesma flexuosa 



prismatica 



phaseolina 



corbuloides 



glabrella 



purpurascens 



nucleola 



physoides. 



CORBULA. 



Encyl. Method, pi 230, fig. a, b, c. 

 This genus approximates those of Crassatella and Un- 

 gulina, but is eminently distinguished from them by the 

 inequality of the valves,and thestrong primary elevated 

 tooth. Shell regular, inequivalve, inequilateral; only 

 slightly, if at all, gaping; one primary tooth in each 

 valve, conical, curved, and ascendant; at the side a ca- 

 vity; no lateral teeth. Ligament interior, placed in 

 the cavities. 



Corbula australis 

 sulcata 



erythrodon 

 ovalina 



Corbula Taitensis 



nucleus 



impressa 



porcina 



Corbula semen. 

 [And four fossil species.] 



