Explanation of Plate. 



The specimens are in the collection of the Museum of the 

 Buffalo Society of Natural Sciences. They all come from the 

 Bertie waterlime (Monroan) of North Buffalo. The illustrations 

 are natural size. 



Fig. 1. Hercynella buffaloensis, sp. nov. Top view of 

 type specimen, showing assymetric position of apex. 



Fig. 2. Front view of same. 



Fig. 3. Side view of same. 



Fig. 4. Hercynella patelliformis, sp. nov. Top view of 

 type specimen. 



Fig. 5. View of right side showing gentle slope. 



Fig. 6. View of left side showing steep slope. 



