PLATE XXXI. 



Page 

 Unio ligamentinoides Lea 249 



Fig. I. View of the right side of Mr. Lea's type of the species. 

 Unio pb^anodontoides Whitfield 250 



Fig. 2. View of the type specimen. 

 Unio Roanokoides Lea : 248 



Fig. 3. Outline cardinal view of a large specimen of the species. 

 Unio humerosoides Lea 248 



Fig. 4. View of the right side of Lea's type specimen. 



330 



