148 



NORTH AMERICAN INDEX FOSSILS. 



two or three lateral lobes pointed and tongue-shaped ; saddles spatu- 

 late and rounded ; antisiphonal lobe long and pointed, flanked by 

 a pair of short, rounded lobes, Mississippic-Carbonic. 



231. P. greenii (Miller). (Fig. 1398, /,^.) Mississippic. 



''*''"Y^"T'"Y^' .f|fftti> 



w. 





Fig. 1398. a, b, Prodromites gorbyi, X % "> <^' ^t Prolecanites cu?npaftus, X /^ 5 

 e, suture enlarged ; f,g, P. greeni, X Yi '•> ^^~J-> ^- fyoni, shell X %> ^^^ suture en- 

 larged. (All after J. F. Smith.) 



Small, discoidal, evolute, slightly embracing; whorls elliptical in 

 section, with narrow, rounded venter; septa close and lanceolate, 

 with short, pointed, tongue-shaped' or dart-shaped ventral lobe, 

 flanked by two similar laterals ; saddles rounded and club-shaped. 



Kinderhook of Indiana. 

 232. P. lyoni (M. and W.). (Fig. 1398, /i-y.) Mississippic. 



Like the preceding but larger, with more whorls which increase 

 less rapidly, with pointed ventral lobe and slightly mucronate 

 lateral lobes and rounded saddles. 



