NOTE ON THE "PELVIC WING" IN POULTRY 1 



PROFESSOR WILLIAM A. LIPPINCOTT 

 Kansas Agrkti/itral Experiment Station- 



Quite recently P>eel>e (.1915) proposed a four-wing 

 theory of the origin of flight in birds in the stages suc- 

 ceeding the arboreal phase of their evolution. Osborn 

 (1918) raises this theory to the position of an alternate 

 with the older two-wing theory developed from studies 

 on the Arcluroptervx (see ITeilmann, 1913). Beebe bases 

 his theory on observations of nestlings of the white- 

 winged dove (Melopelia asiatica) and the domestic 

 pigeon (Columba livia Bonn.), an embryo of the jacana 

 (Jacana jacana), a living specimen of the great horned 

 owl (Bubo virginianus) and studies of photographs of 

 the Merlin specimen of the Archaeopteryx. 



The purpose of this note is to report the presence of 

 the structure described by Beebe, in certain domestic 

 birds. In reporting his discovery of a "pelvic wing" in 

 nestling birds Beebe (p. 42) makes the following state- 



the upper part of the hind-leg, and extending toward the tail across 

 the patagium just behind the femur. A second glance showed that this 

 was no irregular or abnormally precocious development on the part of 

 the femoral pterylum, but a line of primary like sheaths, many of 



He then proceeds to a rather detailed description of the 

 structure which he called a " pelvic wing." 



What appears to be the same structure, judging from 

 Beebe 's description and from the figures accompanying 

 his paper, may be readily observed on most chicks of the 



i Contribution No. 14 from the Department of Poultry Husbandry. 



