CEPHALOPODA— AMMONOIDEA. 145 



223. S. hildrethi Morton. (Fig. 1393, J, ^.) Carbonic. 

 Whorls subglobose, helmet-shaped, embracing to umbilical 



shoulder of preceding whorls ; umbilicus deep, nearly one third 

 of total diameter; shoulder abrupt and noded or ribbed. 

 Upper Coal Measures of Ohio; Cisco of Texas. 



LXXXVIII. Paralegoceras Hyatt. 



Differs from Gastrioceras in its higher, transversely compressed 

 whorls, narrower umbilicus, less pronounced sculpture, and long 

 and narrow lobes and saddles, the former being eleven pairs in all. 

 Mississippic-Permic. 



224. P. iowense M. and W. (Fig. 1396.) Mississippic-Carbonic. 



Fig. 1396. Paralegoceras iowense, shell X%» ^"^ suture enlarged. (After Smith.) 



Large, nearly flat on sides, with rounded venter and with shallow 

 umbilicus about one half the width of last whorls. 



Bend formation of Texas ; Middle Coal Measures of Iowa. 



Pop A NO CER ATID A . 



LXXXIX. PoPANOCERAS Hyatt. 



Involute, slightly compressed goniatites, with almost closed 

 umbilicus and little sculpture ; saddles rounded and entire ; external 

 lobes four or more in number on each side, serrated, either bifid 

 or trifid. Carbonic-Permic and Triassic. (Parapopanoceras.) 



