1 172 



CLASS REPTILIA. 



the inner aspect ; and owing to a confusion between the proper inner 

 and outer sides of the English specimens, only recently cleared up, it 

 has been considered by some palaeontologists that there was an essential 

 difference between the structure of the pelvis of the English and Amer- 

 ican forms. 



The femur in its straight shaft and absence of an inner trochanter 

 likewise resembles to a considerable extent that of the Crocodilia ; 



Fig. 1073. — The left side of the pelvis of Brontosaumcs excelsus; from the Upper Jurassic of 

 North America. One-sixteenth natural size, a, Acetabulum ; il, Ilium ; is, Ischium ; p, Pubis ; 

 /, Foramen in do. (After Marsh.) 



although its head is not laterally compressed to the same extent, nor 

 placed so obliquely to the distal condyles. 



In time this suborder ranges from the Upper Trias to the Cre- 

 taceous, and it is especially well represented in the Kimeridge Clay 

 and Wealden of Europe. 



