ORDER PYUOPODES— THE DIVING BIRDS. 251 



Order PYGOPODES — The Diving Birds. 



Characters. Legs inserted far backward, the tarsi extremely compressed. Antei ior 

 toes fully webbed or else strongly lobe i and with broad flat nails (PodicipicKe). Bill ex- 

 tremely variable. Habits praecocial in Podicipidce and Colymbidce, altricial in Alcidce; 

 young dasypaedic. Palate schizognathous. Carotids double, except in Podicipidce and 

 some Alcidce (e. g.< genus^4ZZe). 



The following Families are referred to this Order in the Ameri- 

 can Ornithologists' Union Check List: 



A. Tail-feathers wanting, (Suborder Podicipedes.) 



1. Podicipidae. Anterior toes lobed, the nails very broad and flat, with rounded tips. 



B, Tail-feathers present, but short. (Suborder Gepphi.) 



2. Urinatoridse. Hind toe present. 



3. Alcidae. Hind toe absent. (Not represented in the Illinois fauna.) 



According to Seebohm," the Alcidce should be removed 

 from any close association with the PodicipidcB and Urma- 

 toridce, which that author unites in a so-called Order which 

 he terms " Colymbo-Podicipes." The latter he considers as repre- 

 senting "highly specialized Penguins,'' while the Alcidce he re- 

 gards as "Archaic Gulls."* 



Even the Penguins (Family SpTierbiscidce) have been placed by 

 some authors among the Pygqpodes, but there can be no doubt 

 as to the very great remoteness of their relationship. 



* The Puis, October. 1888, pp. 133-134. 



