1892.] CLASSIFICATION OF BIRDS. 251 



IV. Trogones. 



Tropical. Frugivorous. 



10 primaries. Oil-gland nude. No downs in adults. 



Schizognathous. Basipteiygoid processes rudi- 

 mentary. 



15 cervical vertebrae. 



Spina externa long, forked. Coracoids touching each 

 other. 



Hypotarsus complex. 



Flexors of type VIII. {Unique.) 



Intestinal convolutions of type VI. 



Caeca functional. 



1. TrogonidcB. 



V. CoRACIiE. 



Cosmopolitan. 



Desmognathous. Basipterygoid processes absent, or 



(Coi-aciidce) sometimes rudimentary. 

 14 or 15 cervical vertebrae. 

 Hypotarsus complex. 

 Syrinx tracheo-bronchial. 



1. CoraciidcB. 



Palaeogaean. Zoophagous. 



Dorsal pterylosis with apterium. 



10 primaries. Oil-gland nude. 



No downs in adults. 



1 4 cervical vertebrae. 



No spina interna. 



Procoracoid process large, but not fusing with 



the acrocoracoid. 

 Eight and left carotids present. 

 Cieca functional. 



2. Momotidce. 



Neotropical. 



Without dorsal apterium. 



10 primaries. 



No downs in adults. 



Spina interna absent. 



Coracoids separate. 



Procoracoid process very small. 



15 cervical vertebrae. 



Right and left carotids present. 



3. Alcedinidce. 



Zoophagous. Cosmopolitan. 



Without dorsal apterium. 



1 1 primaries. Oil-gland tufted. 



