PLATE XXIII/. 



Bones of two individuals of Periptychus rhabdodon, from the Pnerco formation of New Mexico, natural 

 size. All belong to one individual excepting figs. 4, 5, 6, and 7, which belong to a second and 

 rather larger one than the t'oimer. The accompanying jaws and teeth are not figured. Page 391. 



Fig. 1. — Superior view of cast of roof of brain case. 



Figs. 2-7. — Cervical vertebrae, one, the third or fourth, missing ; views of the right side ; o, inferior 

 views; b, anterior views. 



Figs. 8-9.— Caudal vertebrie, right side; a, below; b, posterior view; o, left side of No. 9. 



Fig. 10. — Proximal part of scapula, interior view ; a, glenoid cavity. 



Fig. 11. — Right humerus, the front ; a, posterior side ; b, proximal ; c, distal extremities. 



Fig. 12. — Left ulna, interior view; a, exterior view; b, superior view. 



Fig. 13. — Head of radius, proximal view. 



