1224 CLASS AVES. 



Toothed Series. — In this extinct series teeth are present in 

 the jaws. 



Suborder i. Odontolcte. — The type and only known repre- 

 sentative of this suborder is Hesperornis, of the Cretaceous of North 

 America. In this remarkable Bird (fig. 1113) the jaws (fig. 11 17) 

 were provided with a series of sharp-pointed teeth, sunk in a deep 

 continuous groove ; but the anterior portion of the upper jaw was 



Fig. 1 1 13. — Skeleton of Hesperornis regalis', from the Cretaceous of North America. 

 About one-tenth natural size. (After Marsh.) 



edentulous, and probably sheathed in a horny covering like that of 

 existing Birds. Various parts of the skeleton are represented in 

 figs. 11 11, 1 1 12, and 1 1 17. 



In its whole skeletal organisation Hesperornis conforms strictly to the 

 existing Ratite type ; but there were four digits in the pes (all of which 

 were directed forwards), and Professor Marsh believes that it was of 

 aquatic habits, and compares it to a swimming Ostrich. According to 

 the description of the same authority, the tail consists of about twelve 

 vertebrae, of which the last three or four are amalgamated to form a flat 





