EXPLANATION OF PLATE 15. 



Pelvic arch Camptosaurus dispar Marsh. N... 187S. Yale Museum. Para- 

 type One-fifth nat. size. Internal view of right side : a, acetabulum ; il, ilium : 

 is, ischium; p, pubis: //. postpubis; x, depressions for articulatiou of sacral 

 ribs. From a photograph. 

 322 



I 



