//. TYPES IN DETAIL IVITH THEIR SUBORDINATE GROUPS. 45 



Sub-class II. ODOMIORBITHES. . . . , " Toothed-birds, " a group based 



upon fossil, bird-like forms, found 

 in the cretaceous beds of Kansas 

 and Colorado. The remains repre- 

 resent two types, suflSciently dis- 

 tinct to constitute different orders. 

 Order I. Odontoholc^ Ratite birds, with teeth in con- 

 tinuous alveolar grooves; halves of 

 mandible united by cartilage; 

 wings much reduced, containing 

 humerus alone; caudal vertebrae 

 expanded and paddle-like. Feet 

 fitted for swimming. 



X Hesperornis, Lestornis. 



Order 2. ODONTORMiE Carinate birds with teeth set in 



separate sockets; halves of man- 

 dible united by cartilage. Wings 

 strong and powerful. 



X Ichthyornis, Apatornis. 



Sub-class III. EURHiPiDuiLff; This sub-class includes all living 



birds. They are toothless, with 

 two halves of the mandible anchy- 

 losed; a short tail ending in a 

 pygostyle of several fused vertebrae. 



Order i. DROMiEOGNATHi Running birds with rudimentary or 



small wings and large, heavy legs. 

 An important anatomical character 

 is the dromKognathus skull, i.e., 

 one in which the palatine bones 

 are separated from the rostrum by 

 a wide vomer. Feathers of the 

 down type (rami not united). 

 This Order includes the old group 

 of " Ratiiae," besides a few others, 

 extinct and recent, some being 

 carinate. 



X Slruthio, Apteryx, Tinamus. 



