THE EMPIRE OF THE GREAT REPTILES. 173 



reptiles, and their subsequent distribution between the very 

 dissimilar types in which they are now continued. 



The approximation of the winged reptiles to the birds is 

 urther increased by the facts that in the Jurassic and Creta- 

 ceous periods there were birds having reptilian tails and 

 probably toothed jaws {Archaopieryx macroura, Fig. 148). 

 The species just named, while in its limbs, trunk, and feathers 

 a veritable perching bird, resembles a reptile in its head and 

 tail. In the Cretaceous of Western America, Marsh has re- 

 cently discovered two distinct types of toothed birds, one 

 having the teeth in regular sockets, the other having them 

 implanted in a groove in the jaw. One of these birds 



nAMd fil^LuLAii 



Fir,. 149.— Jaw of a Crttaceous Tocthed Bird (Ichthyomis th's/-ar).—Ahtr Marsh. 



Natural size. 



{Ichthyornis dispai', Fig. 149) was as large >as a pigeon, with 

 powerful wings constructed like those of ordinary birds. It 

 had also the curious and old-fashioned peculiarity of bicon- 

 cave vertebrae, like those of fishes and some reptiles. Another 

 {Hesperornis regalis) stood five or six feet high, and had rudi- 

 mentary wings like those of the Penguins. These toothed 

 birds extend into the Eocene Tertiary, where the Odontopteryx 

 of Owen has been known for some time. In the Eocene, 

 however, this toothed bird is associated with others of ordinary 

 types, allied closely to the Ostriches, the Pelicans, the Ibis, the 

 Woodpeckers, the Hawks, the Owls, the Vultures, and the ordi- 

 nary perching birds. In the Later Mesozoic, indeed, some 

 reptiles became so bird-like that they nearly approached the 

 earliest birds ; but this was a final and futile effort of the 

 reptile to obtain in the air that supremacy which it had long 



