88 COPE 



Cretacic of Middle North America. They have many of 

 the characters of the divers (order Cecomorphfe). 



To the Odontotorm^ one order only is referred. It is 

 thus characterized : 



Teeth in sockets ; sternum keeled ; vi^ings 

 well developed ; ischium and pubis free 

 posteriorly ; vertebrte biconcave ; Pteropappi. 



The family of the Ichthyornithidse is the only one 

 known to belong to the Pteropappi. Its members are 

 known from the Upper Cretacic of North America and the 

 Lower Cretacic of England. 



The EuoENiTHES include numerous suborders, wliich are 

 defined as follows : 



1. Maxillopalatines united across the middle of the 

 palate. (Desmognathse). 



A. Four toes directed forwards (pamprodactyl- 

 ous). 



Toes webbed ; .no basipterygoids ; (1) Steganopodes. 



Toes free ; vomer unossified ; no basi- 



pterygoid processes ; (2) Colioidei. 



AA. Three toes directed forwards.* 



Short basipterygoid processes ; toes gen- 

 erally webbed ; prsecocial ; (3) Chenomorphas. 



No basipterygoid processes ; bill and legs 

 slender ; toes generally free ; altri- 

 cial ; (4) Herodii. 



Bill and claws hooked ; toes free ; ver- 

 tebrae saddle-shaped ; altricial ; (5) Accipitres. 



Bill hooked ; toes free ; vertebrae opis- 

 thocoelous ; rostrum movably ar- 



*Except Caeulidse and Rhamphastidse, which are zygodactyloiis. 



