° i906 J Clark, Pterylosis of Swifts and Hummingbirds. 69 



probability at present of securing in this country further material 

 of importance, I have decided to delay no longer the publication 

 of this account of the work that has been done and the conclusions 

 reached. 



It is an interesting fact that the pterylography of no group of 

 birds has received so much attention as has that of the swifts and 

 hummingbirds. The classic work of Nitzsch ('40) deals quite 

 fully with the matter, so far as his material and methods allowed. 

 Shufeldt ('88) has given a very full account of the pteryloses of both 

 swifts and hummingbirds, making use however of Nitzsch's fig- 

 ures, which are, unfortunately, very inaccurate. Lucas ('92) has 

 described the pterylosis of the hummingbirds in Ridgway's paper 

 on that group, giving figures of the dorsal and ventral aspects of 

 Florisuga meUivora. Thompson (:01) has described in full, and 

 figured well, the pterylosis of Patagona gigas, compared it with 

 both Capri mulgus and Collocalia, and given a figure of the dorsal 

 aspect of the latter. His conclusions were criticised by me in 

 'Science' (January 17, 1902) and Shufeldt published a counter 

 criticism in 'The Condor' (March-April, 1902), to which a brief 

 reply was made in the next issue of the same journal (May-June, 

 1902). Discussion centers around the question whether the swifts 

 and hummingbirds have essentially distinct and unique pteryloses 

 or not, and to this question we shall return when we have completed 

 an examination of the evidence in the case. The pterylography 

 of the swifts will be considered first, a brief general description 

 of the cypseline pterylosis being followed by a short account of 

 each genus examined. The account of the hummingbirds follows 

 in the same way, after which the two groups are compared, and 

 final conclusions stated. 



In this connection I wish to thank Mr. Lusk, Mr. Taylor, Mr. 

 Stone, and especially Mr. F. A. Lucas, for the help they have given 

 me in securing the needed material, without which nothing could 

 have been done, and to Mr. Stone and Dr. J. A. Allen, I am indebted 

 for assistance in nomenclature. 



