Order pygopodes— the diving birds. 251 



Order PYGOPODBS.— The Diving Birds. 



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

 toes fully webbed or else strongly lobei and with broad flat nails {Podioipidw), Bill ex- 

 tremely variable. Habits preeoooial in Podicipidw and Colymbidw, altrloial in -Aluidw; 

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

 some Alcidce (e. ff.. genus AUe). 



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

 can Ornithologists' Union Check List: 



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



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



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



2. Urinatoridse. Hind toe present. 



S. Aloidee. Hind toe absent. (Not represented in the Illinois fauna.) 



According to Seebohm,* the Alcidce should be removed 

 from any close association with the Poddcvpidm and TJrma- 

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

 he terms '■'• Oolymho-Podidpes.'''' The latter he considers as repre- 

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

 gards as "Archaic Gulls." 



Even the Penguins (Family Sphenisoidm) have been placed by 

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

 as to the very great remoteness of their relationship. 



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



