366 Mr. E. Hartert on some Species of 



explained. Indeed, the relationship of many forms is the 

 better understood the more subspecific forms are recog- 

 nized (supposing that there is any foundation for them) ; 

 and it being evident that such forms exist, they 7nnst, in my 

 opinion, be recognized, because to disregard them altogether 

 is as unscientific as to treat them as well-defined species. It 

 is impossible to deny the existence of subspecific forms, and it 

 is wrong to treat them as species, because intermediate forms 

 occur; therefore we must agree that the scientific systematic 

 treatment of living animals demands the recognition of sub- 

 species, if systematic zoology is to be more than a pastime, 

 and if it is to take the important place in science which it 

 ought to hold. 



The Genus Micropus. 



In the genus Micropus {Cypselus, auctt. mult.) I have to 

 recognize two more species — i. e., M. shelleyi, Salvad., and 

 M. ivillsi. With regard to the former, I refer to my remarks 

 on p. 445 of Cat. B. xvi., and have to add that I have seen 

 one more perfectly adult skin (now in the British Museum), 

 which has convinced me that it is a distinct species, resident 

 in the mountains of Shoa and Abyssinia, and characterized 

 by its shorter wing (6*1 in.) and shorter (2'75 in.) and less 

 pointed rectrices. 



I have been looking through my old note-books, and find 

 that in none of the numerous nests of Common Swifts which 

 I have taken and seen on the Continent were there more than 

 two eggs or two young birds. Several of my friends assure me 

 also that they never heard of more than two eggs in a clutch. 

 Nevertheless, in almost every book the number of eggs of 

 the Swift is given as two or three, or sometimes even four. 

 I am anxious to hear from the members of the B. O. U. 

 whether this is, as I believe^ a story repeated from one book 

 into the other, or whether anyone has himself taken a clutch 

 of more than two eggs of the Common Swift. 



M. murinus, Brehm { = M. palhdus, Shelley), which I 

 treated as a subspecies in the Catalogue, is so very distinct 

 from M. apus typicus that most writers regard it as a good 



