CEPHALOPODA— AMMONOIDEA. 



219 



384. P. stantoni Hyatt. (Fig. 1496.) Cretacic. 



Like P. whitfieldi, but with stouter volutions and broader venter ; 



intermediate in character between that species and P. intercalare; 



umbiHcal shoulder abrupt, with a row of sparse tubercles. In the 



Fig. 1495. Placenticeras hitercalare^ and suture. 



variety holli Hyatt coarse, fold-like ribs occur at wide intervals, 

 bifurcating occasionally; venter with elongate tubercles which cor- 

 respond to the costse when they are present. 

 Coloradoan of Upper Kanab Valley, Utah. 



385. P. pseudoplacenta Hyatt. (Fig. 1497.) Cretacic. 



Venter broad, flat or rounded in adult, but with placenta type 

 0"f venter in neanic; suture simpler and more ragged than in P. 

 placenta. 



Coloradoan of Upper Utah; Huerfano Park of Colorado. 



385a. Variety occidentale Hyatt. Cretacic. 



Suture more like that of P .whitfieldi, but lobes and saddles more 

 solid ; a row of tubercles on the umbilical shoulder, and fine tuber- 

 cles on the ventral borders. 



