270 



ORDERS OF BIRDS. 



he has named Ichthyornis disfar and A2mtornis celcr, both 

 from the Cretaceous rocks of North America. 



In Ichthyornis dispar, which may be taken as the type of 

 the order, the teeth (fig. 592, a) were sunk in distinct 

 sockets, and were " small, compressed, and pointed, and all 



Fig. 593. — Skeleton of Hesperornis regalis, restored (after Marsh). About one-tenth 

 of the natural size. 



of those preserved are similar. Those in the lower jaw 

 number about twenty in each ramus, and are all more or 

 less inclined backwards. . . , The maxillary teeth ap- 

 pear to have been equally numerous, and essentially the 

 same as those in the mandible. The skull was of moderate 

 size, and the eyes placed well forward. The lower jaws are 

 long and slender, and the rami were not closely united at 

 the symphysis. . . . The jaws were apparently not 

 encased in a horny sheath. 



