CRETACEOUS ANIMALS. 



489 



longing to the two genera Ichthyornis and Apatornis, were ivffliout 

 the horny Ibeak so characteristic of existing birds, but instead had thin, 



Fig. 819.— Restoration of Ichthyornis victor (after Marsh). One half natural size. 



long, slender jaws, furnished with many sharp, conical teeth, set in 

 sockets, twenty on each side below, and somewhat fewer above (Fig. 

 819). Their vertebrae were amphicoelous or bi-concave, as in fishes and 

 many extinct reptiles, but in no modern bird (Fig. 821). Like modern 

 birds, however, they had a keel on the breast-bone for the attachment 

 of the powerful muscles of flight. The tail also is worthy of atten- 

 tion, being not like that of the Jurassic Archseopteryx, but much 

 shorter and not so reptilian (Marsh). These birds were about the size 

 of a pigeon, and were evidently powerful fliers. Fig. 819 is a restora- 

 tion by Marsh of one of this type. The other toothed birds had similar 



