CEPHALOPODA— AMMONOIDEA. 



i6i 



nitic ; deeply digitate ; distinguished from Trachyceras by the 

 absence of interruption of the ornamentation of the venter. 



260. S. (Trachysagenites) herbrichi Mojsisovics. (Fig. 1408.) 



Triassic. . 



Ornamentation has aspect of close-set, regular spiral rows of 

 spines 



Upper Triassic (Karnic) of California and the Alps. 



Fig. 1408. Sagenites {^Trachysagenites) herbrichi, two views X 

 (After Hyatt and Smith.) 



and suture. 



CXIII. Tropites Mojsisovics. 



Moderately evolute, not deeply embracing, with deep, open um- 

 bilicus with steep walls; whorls usually broader than high, with 

 angular, prominent, umbilical shoulders and arched venter; sur- 

 face with strong umbilical nodes and spiral lines ; septa ammonitic. 

 Triassic. 



261. T. subbullatus Hauer. (Fig. 1409, a-c.) Triassic. 



Subglobose ; section trapezoidal ; venter with low, strong median 

 keel. 



Upper Karnic beds of California, and of Tyrolian Alps ; probably 

 also Himalayas. 



CXIV. DiscoTROPiTES Hyatt and Smith. 



Involute, discoidal, laterally compressed ; venter narrow, acute, 

 with high keel, which is sometimes hollow; surface with dichot- 

 omous, sickle-shaped ribs which become obsolete at base of keel; 

 umbilical nodes and spirals (sometimes with nodes) are present; 

 sutures ammonitic ; body chamber long ; young like adult Tiropites. 



