i8S7-l Correspondence. I *1 1 



sesses features and combination of features quite unique, and shared by no 

 other birds, and especially not by the Swallows. That a Swift hovers in 

 front of its nest before enteringit "like a Hummingbird over a flower," 

 shows certainly no special relationship, for I have seen despised English 

 Sparrows do the same, and as for swift and precipitous flight and its in- 

 stantaneous checking I might quote numerous birds which in their wing- 

 structure show no analogy to that of the Macrochires. The superficial 

 similarities of certain structures in the Swallows' and the Swifts' wings can 

 undoubtedly be traced "to the modification of these structures gradually 

 brought about by the habits or actions of the forms in question," to use 

 Dr. Shufeldt's own phraseology. It is upon the recognition of the essen- 

 tial and the unessential similarities, and of the superficial analogies and 

 the radical affinities, that the present question hinges. 



Yours, very truly, 



Leonhard Stejneger. 

 Smithsonian Institution., 

 December 25, 1886. 



To the Editors of The Auk : — 



Sirs: — Will you kindly allow me a little space in which to reply to Dr. 

 Shufeldt's comments on the footnotes of my recent paper on 'The Affini- 

 ties of Chcztura'? 



At the outset let me say that I object less to the separation of Swift and 

 Hummingbird than to the union of Swift and Swallow. As Dr. Shufeldt 

 now concludes (or did in October last) that the Swifts are not a family of 

 Passeres placed next the Swallows, but an order by themselves, we are 

 less at variance than when the paper on Chcetnra appeared. 



In one and the same paragraph Dr. Shufeldt objects to my statement that 

 Professor Huxley united the Swifts and Hummingbirds, while quoting Hux- 

 ley's own words, which show the statement to have been correct! (p. 86). 

 The remark that Professor Huxley "evidently believed that Swifts were but 

 profoundly modified Swallows" is purely an assumption; but even if it be 

 a correct one, the fact remains that he believed them to be so very "pro- 

 foundly modified" as to require a place in quite a different order. In view 

 of the fact that Dr. Shufeldt has not been in Washington for over two 

 years, it is a little surprising that he should assume to know exactly what 

 material is contained in the collections of the National Museum. Never- 

 theless, Dr. Shufeldt is this time correct in his supposition, for at the time 

 of writing neither Patiyptila, nor Tachycineta thalassina (T. bicolor I 

 did have) were in my possession, although since then crania of both 

 species have been extracted from skins, supplied by the courtesy of Mr. 

 Ridgway, and verify my statement that the maxillo-palatines as figured 

 by Dr. Shufeldt are imperfect. While my specimen of Panyptila is a 

 poor one, having suffered from decalcification, traces of the slender 

 maxillo-palatines still remain, and show them to be practically of the same 

 shape as those of Chcetura, Cypselus apus, and Dendrochelidon mystacea, 



