92 



Cardinal Tooth compressed, elevated, and often 

 lamellar. 



Unio rostrata 



Unio luteola 



pictorum 



marginalis 



Batava 



angusta 



corrugata 



• • • • manca 



nodulosa 



cariosa 



varicosa 



spuria 



granosa 



australis 



• • • • depressa 



anodontina 



.... Virginianum 



suborbiculata 





HYRIA. 



MYA SYRMATOPHORA. Gmelhl. 



Swainsons Exotic Conchology. 

 The genus Hyria is very distinct from the preceding 

 genus, not only in general form, but in the shape of the 

 cardinal tooth, particularly that of the right valve. They 

 much resemble the Aviculae in shape, and probably in- 

 habitlakes, rather than rivers. The cardinal, or posterior 

 tooth, is divided into many lamellar plaits or pieces, the 

 centre ones very small, and presenting the appearance 

 of an assemblage of divergent, and very unequal sized 



