FOSSIL MEDUS4 IN THE NIAGARA LIMESTONE 751 
Fics. 5-7. Cryptodiscus digitatus. 
5. Two quadrants detached but still holding their relative position. 
Possibly a distinct species. 
6. The lower side of the type specimen. 
7. The upper side of the type specimen. 
Fig. 8. Cryptodiscus bilobus. 
The type specimen. 
STUART WELLER. 
WALKER MUSEUM, 
University of Chicago. 
