AYES. 



KEY TO THE ORDERS. 



a. Young born helpless, and not able to avail 

 themselves of the instinct of self-preserva- 

 tion for, at least, the first twenty-four hours. 

 o 1 . Young do not pass through a downy 

 stage before acquiring feathers, unless 

 the species is nocturnal as in the 

 Caprimulgidce. 

 a 2 . Palate segithognathous, and the deep 



plantar tendons free 1. Passeeifoemes. 



b". Palate never aegithognathous when the 

 deep plantar tendons are free. 

 a 3 . Palate never schizognathous when 



the nasals are schizorhinal ... 2. Picifobmes. 

 b s . Palate schizognathous, and the 



nasals schizorhinal 3. Columbifoemes. 



b 1 . Young pass through a downy stage before 

 acquiring feather. 

 c 2 . Not web-footed. 



c 3 . Dorsal vertebrae opistoccelous ; feet 

 always zygodactyle ; young born 



naked 4. Psittacifoemes. 



d 3 . Dorsal vertebrae heteroccelous. 

 a*. Feet generally zygodactyle ; young 



born covered with down ... 5. Accipiteifoemes. 

 6 4 . Feet never zygodactyle ; young 



born nearly naked 6. Aedeifoemes. 



d 2 . Web-footed. 



e 3 . Palate desmognathous ; all four toes 

 connected by a web ; young born 



nearly naked 7. Pelecanifoemes. 



f 3 . Palate schizognathous ; hind toe not 

 connected to the other toes by a 

 web; young born covered with down. 



[Juue, 1SSJ9. i 



