EXPLANATION OF PLATE XV. 



Fig's. 28. — A and B Cumherlandia monodonta (Say) 9, Miss. R. 



LaGrange. 



Fig's. 29 A and B. — Fusconaia tuidata (Barnes) 9, Miss. R., Hannibal 

 Fig's. 30 A and B. — Adult F. undata trigonoides Frierson MS. Z 



Platte R., Agency Ford. 



Fig's. 30 C and D. — Juvenile of trigonoides. 



Fig's 31 A and B. — F. undata trigona (Lea) 9, Osage R., Warsaw. 

 Fig's. 32 A and B. — Adult F. flava (Raf.) cf, White R., HnlHster 

 Fig's 32 C and D. — Young of flava. 



Fig's 33 A. and B. — F. hebetata (Conrad) 9, Osage R., Warsaw- 

 Fig's 34 A and B. — F. ebena (Lea) 9 , Miss. R., LaGrange. 



