1892.] . CLASSIFICATION OF BIRDS. 253 



I. PiCI. 



Zygodactylous, or hallux absent. 



Nestling and adult downs absent. Nesting in holes. 



14 cervical vertebrae. 



Flexors of type VI. (Unique.) 



Intestinal convolutions of type VII. (Galbula and 



Bucco unknown.) 

 Caeca absent, except in Galbulidce. 



1. Galbulidce (Galbulinse + Bucconinae). 



Desmognathous. 



Spina externa forked. Right and left carotids. 

 Oil-gland nude in Galbulince and in most Buc- 

 conincB. 



2. Picidce (Picinse, Yunginse). 



Schizo-segithognathous. 



Spina externa forked. 



Oil-gland tufted. Left carotid only. 



3. Capitonidce (CapitoninEe -1- Indicatorinse). 



-^githo-desmognathous. 



Spina externa unpaired. 



Oil-gland tufted. Left carotid only. 



4. RhamphastidcB. 



Frugivorous. 



Desmognathous. 



Spina externa unpaired. 



Oil-gland tufted. Left carotid only 



II. Passeres. 



JEgithognathous. 



Hallux present ; 2nd, 3rd, and 4th toes always turned 



forwards. 

 Nestlings with downs of complex structure. 

 Oil-gland nude. Left carotid only. 

 Caeca not functional. 

 Intestinal convolutions of type VII. or VIII. 



1. EurylcemidcB, 



Indian. Austro-Malayan. 

 Hallux weak ; front toes syudactyle. 

 15 cervical vertebrae. 

 Spina externa long, single. 

 Intestinal convolutions of type VIII. 

 Flexors of type I. 

 Oligo-mesomyodous. 

 Prog. Zool. Soc— 1892, No. XVIII. 18 



