32 



proceedi:n'GS of the national, museum 



VOL. 66 



area commences 23.5 mm. below tuberculum and extends downward 

 for a distance of 38 mm. 



The neck of the fifth rib (pi. 14, fig. 5) is also narrow, with its 

 depth greater than its breadth. The tuberculum is sub-triangular in 

 outline and about equally as long as broad. The internal margin 

 of this articular facet rolls over upon the shaft and the external face 

 of the shaft is not so noticeably flattened as on the fourth rib. 



The neck of the sixth rib (pi. 14, fig. 6) is even narrower, but the 

 depth and breadth are about equal. The capitulum and tuberculum 

 are about equal in area. As in case of the fifth rib, the internal 

 margin of the tuberculum likewise rolls over upon the shaft, and the 

 external face is more rounded. 



On the ninth rib (pi. 14, fig. 7) the facets for articulation with the 

 rudimentary diapophysis and parapophysis are combined into a sin- 

 gle articular head. The tenth rib (pi. 14, fig. 8) is characterized by 

 having a long narrow articular head for the parapophysis. Near the 

 middle the width and depth of the shaft are about equal. All the 

 ribs thin out near their lower extremities. 



Measurements of ribs in millimeters 



1 Capitulum to extremity. 



' Tuberculum to extremity. 



' Combined facets for diapophysis and parapophyses. 



INDIVIDUAL 2 



Skull, Cat. No. 10714, Section of Vertebrate Paleontology, United 

 States National Museum. 



Some difficulty was encountered while excavating around this 

 skull in preparation for its removal from the cliff, and unfortunately 

 it was fractured in several places. The top of the cranium (pi. 15, 

 fig. 1) and most of the rostrum was removed in good condition. 



