POPANOCERAS. 133 



species has only a generic resemblauce to the forms from tlio Ural 

 Mountains and the Fusulina limestone of Sicily, all of which ])elong to the 

 Permian, and are therefore usually more complex in development. 

 Dimensions of the figured specimen : 



Millimeters. 



Diameter 25 



Height of last whorl 14. 5 



Height of last whorl from the preceding 0. 5 



Width oi last whorl IC, 



Involution H 



Width of umbilieus 1. ,5 



This form is more globose and primitive than most of the described 

 species of this genus, and it is next to the oldest known member of 

 Popanoceras, the oldest being F. jxirkeri of the Middle Coal Measures. 



Occurrence. — Upper Coal Measures, Cisco formation, Graham, Young 

 County, Tex., collected by A. B. Cant. Type No. 27202 in the U. S. 

 National Museum. 



Popanoceras parkeri Heilprin. 



PI. XVI, fig. 21. 



18S-i. Amvwiilti-a parheri. A. Heilprin. Proc. Acad. Nat. Sci. Phila., 1884, p. 53, 



figs. 1 and 2. 

 188'.t. Pojxmocerdx jxtrh'r! , A. Karpinsky, Animoneen der Artinsk-Stufe, p. 7.5. 



Shell subglobose involute, abdomen rounded, sides somewhat flattened, 

 whorls high and deeply embracing. 



Septa divided into numerous lobes and saddles; the lobes are all 

 digitate, the saddles entire and rounded, except the siphonal saddle, which 

 is notched. Ventral lobe long and bifid ; first lateral lobe like the ventral, 

 but shorter and broader; second lateral tripartite, and broader than the 

 first; third lateral on the umbilical shoulders. 



Occurrence. — Middle Coal Measures, Straw n formation, Wise County, 

 Tex. F. Freeh" refers to these beds as Permian, but they are some 

 distance below the Cisco formation, and associated not with a Permian 

 fauna, Ijut with undoubted Coal Measures species. The Strawn formation 

 lies several thousand feet below the Wichita Permian. 



a Die Dyas, p. 510. 



