ORDER PYUOPODE8— THE DIVING BIRDS. 251 



Order PYGOPODES.— The Diving Birds. 



Characters. Legs inserted far backward, the tarsi extremely compressed. Anterior 

 toes fully -webbed or else strongly lobed and with broad flat nails iPodicipidcE). Bill ex- 

 tremely variable. Habits prascocial in Fodicipidoe and ColymhidcE, altricial in Alcidae; 

 young dasypffidic. Palate schizognathous. Carotids double, except in Podicipidae and 

 some Alcidce (e. g„ genus Alle). 



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

 can Ornithologists' Union Check List: 



A. Tail-feathers wanting, (Suborder Pod/ci/jfides.) 



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



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



2. Urinatoridae, Hind toe present. 



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



According to Seebohm,* the Alcidce should be removed 

 from an}^ close association with the Podiclpidce and TJrina- 

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

 he terms ^^ Colymho-Podiclpesy The latter he considers as repre- 

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

 gards as "Archaic Gulls." 



Even the Penguins (Family Spheniscidw) have been placed by 

 some authors among the Pygopod^s, but there can be no doubt 

 as to the very great remoteness of their relationship. 



• The Ibis. October, 1888. pp. 433-434. 



