CEPHALOPODA— ORTHOCHOANITES. 79 



XXIX. Ryticeras Hyatt. 



Cyrtoceracones and gyroceracones similar to preceding, but 

 larger and with coarser, crenulated bands often expanded into 

 spout-like, spinous processes, which sometimes form coarse, longi- 

 tudinal ridges ; siphuncle ventral, less nummuloidal, and larger 

 than in preceding. 



^y. R. jason Hall. (Fig. 1295.) Devonic. 



Fig. 1295. Ryticeras Jason, XVz- (After Hall, Pal. N. Y., V.) 



Large and robust cyrtoceracones of subcircular transverse sec- 

 tion; septa regular; growth lamellae expanding at regular intervals 

 into sharp, foliate and coarse spinous processes. Siphuncle mar- 

 ginal, sometimes exposed by weathering. 



Schoharie and Onondaga of New York. 



