DIVISIONS OF BIRDS. 307 



fessor Marsh. In this Bird (fig. 221) we have a gigantic diving- 

 bird, standing some five feet in height, but with the wings quite 

 rudimentary, so that the power of flight was entirely absent. The 

 tail w^as not elongated, as it is in Archceopteryx, but consists of about 

 twelve vertebrsB, of which the last three or four are amalgamated 



-Skeleton of Hesperornis regalis, restored. (After Marsh.) 

 About one-tenth of the natural size. 



to form a single mass. The bodies of the vertebrae have the form 

 usual among Birds. The jaws are furnished with numerous conical 

 recurved teeth, sunk in a deep continuous groove. The metacarpal 

 bones are wanting, and the sternum is destitute of a keel. 



Order III. Odontotorm^. 



This order comprises only some singular fossil Birds from the 

 Cretaceous rocks of North America, of which the genus Ichthyornis 



