PLATE 41. 



Page. 

 Fig. 1. Unio subspatulatcs : 518 



1, a. Dorsal view of the exfoliated type-specimen. 

 1, 6. A left-side view of the same. 



Fig. 2. Unio Deweyanus 519 



2, a. Exterior of an exfoliated left valve of the typo-specimen. 

 2, b. Hinge and interior of same. 



2, c. Au imperfect right valve, showing parts of tho hinge and interior. 



Fig. 3. Unio Danje 517 



3,0. Left view of the exfoliated typo-Bpeciiuen. 



3, 6. Dorsal view of same. 



3, c. Right-side view of same. [The radiating stria: seen on this aud the other species are 

 only defined on the lamina: whore the epidermis has been removed.] 



