236 



DINOSAURS OF NORTH AMERICA. 



have been derived from some common ancestor of a generalized primi- 

 tive type. The known transformations of this same pelvic element in 

 one other order of dinosaurs (the Predentata) show that the modifica- 

 tions here suggested are well within the limits of probability. The hind 

 limb of one genus of this order is shown in fig. 01 (p. 233). 



04 



05 



GO 



Fig. 64— Pelvis of Ceratosaurus nasicornis Marsh; seeu from the left. One-twelfth natural size. 

 Letters as in fig. C3. 



Fig. 65.— United metatarsal bones of Ceratosaurus naticornti; left foot; front view. One-fourth 

 natural size. 



FIG. 06.— United nu-tatarsal bones of great penguin [Aptenod'ytes PennantU G R.Gr.): left foot, 

 front view. Natural size. 



