CEPHALOPODA— AMMONOIDEA. i8i 



surface with strong, curved ribs, which are prominent over half 

 the side, and in the young converge forward on the broader side. 



Coloradoan of Texas. 

 303. B. compressus Say. (Figs. 1435, 1436.) Cretacic. 



Fig. 1436. Bacuhyes com/>ressus, suiiire enlairged. (After Meek.) 



Large, regularly and rather rapidly tapering, compressed, ovate, 

 with narrowly rounded venter ; suture with strongly incised lobes 

 and saddles. 



Pierre of Upper Missouri and Dakota, and elsewhere ; Ripleyan 

 of New Jersey. 

 304. B. ovatus Say. (Figs. 1437, 1438.) Cretacic. 



Fig. 1437. Bacu/i^es ovatus, cross section. (After Meek.) 



Large, gradually tapering, more broadly ovate than preceding; 

 suture somewhat less finely incised. 



Ripleyan of New Jersey, Alabama, etc. ; Pierre of Dakota, Mon- 

 tana, Colorado, etc. 



Fig. 1438. Bacu/i/es ovatus, septum much magnified. (After Meek.) 



