PLATE LXXXII 



PAGE 



Figs. 1-6. PLATYCERAS MAGNIFICUM Hall 472 



1. Ventral view of a young shell. 



2, 3. Dorsal and ventral views of a larger specimen with free volutions. 



4. Ventral view of a specimen with the volutions free and the peris- 



tome less expanded. 



5. Upper view. 



6. Upper view of the spire of a large specimen in which all the parts 



are symmetrical and well preserved, and the volutions are free 

 except at the extreme apex. 



Oriskany formation, Ridgely member, Cumberland. (After 

 Hall.) 



Figs. 7, 8. PLATYCERAS STJBFALCATUM Ohern n. sp 472 



Side and dorsal views. Oriskany formation, Ridgely member, Han- 

 cock. 



