214 NORTH AMERICAN INDEX FOSSILS. 



372. E. belviderense (Cragin). Comanchic. 

 Sides and venter flat and smooth, with nodes on umbiHcal shoul- 

 ders and alternating nodes on each side of the ventral flattening. 



Champion shell bed and Kiowa shale, basal Washita, Kansas. 



373. E. serpentinum (Cragin). (Fig. 1487, a-c.) Comanchic. 

 Smaller than preceding, with slightly concave venter bordered 



by two ridges, and coarse, alternating ribs instead of nodes, though 

 the latter may appear in gerontic individuals; suture very simple. 

 Upper Washita (Denison) of Texas. 



374. E. hilli Bohm. (Fig. 1488.) Cretacic. 



l^iG. 1488. Engonoceras hilh, suture line. (After Lasswitz.) 



Narrowly umbilicate ; sides gently convex, converging to the flat 

 venter, which is bounded on each side by a low ridge; surface 

 smooth ; suture more complicated than most species of the genus. 



Austin chalk of Texas. 



CLXV. Metengonoceras Hyatt. 



Like Engonoceras but with grooved venter {P rot engonoceras 

 stage) only in the very young, the adult acute and rounded in the 

 old-age stage; saddles numerous, phylliform; lobes narrow, with 

 several marginals. Comanchic-Cretacic. 



375. M. dumblii (Cragin). (Fig. 1489.) Cretacic. 



Last portion of last whorl narrowly rounded, sides gently arch- 

 ing; marginal notches of lobes long and slender. 



Eagle Ford shales (Coloradoan) of Texas. 



CLXVL Sphenodiscus Meek. 



Adult much like Metengonoceras, but young without the grooved 

 venter, the rounded nepionic venter passing directly into an acute 

 neanic, with flattened sides as in the adult; surface smooth or with 

 costse or tubercles. Cretacic. 



I 



