STUDIES OP THE MACHOCniEES. 



339 



As the external characters of these commoner American forms 

 are well known, and are fully set forth in general works upon 

 ornithology, I need not introduce them here. 



Suffice it to say that these characters fully rank as oi^dinal 

 ones in so far as they distinguish these birds from either the 

 Swifts or the Humming-birds. 



When I say ordinal ones I mean as pertaining to an order in 

 the sense which that division liolds as aj^plied to Avian taxonony, 

 and not to other vertebrate classes, where, as we know, structural 

 differences are far greater than are to be found even among 

 the extremes in the class Aves. 



Having gone carefully over all the literature and material now 

 available that bears in any way upon the present group, I find 

 no reason to change my opinion as originally set forth in my 

 memoir published in the Proc. Zool. Soc. 1885, where I proposed 

 (p. 914) that all the Caprimulgine birds should be considered 

 as constituting an order — the order Capkimulgi. I men- 

 tioned a number of the more doubtful forms that should be 

 admitted to this order, as Nijctihius, Steatornis, Podargus, and 

 others. Scarcely a doubt exists now, I think, in regard to the 

 relation these birds bear to the Owds, through Steatornisy and, 

 further, they have no particular affinity either with the Humming- 

 birds nor the Swifts. 



Their morphology is full of interest, and will repay very careful 

 research in the future. 



In the present connection it is my intention to lead off with a 

 full description, if the one fine specimen in my possession will 

 admit of it, of the anatomy of our common American Whip- 

 poor-will (Antrostomus vociferus), making it comparative with 

 the more aberrant genus Chordeiles, and then add something 

 further in regard to the skeleton of Fhalceno'ptilus Nuttalli. 



On tJie PterylograpTiical tracts of Antrostomus and Chordeiles 

 {omitting the remiges and rectrices). 



Having carefully plucked my specimen of Antrostomus voci- 

 ferus and one of Chordeiles texensis, and opened before me my 

 copy of Sclater's edition of Nitzsch's ' Pterylography ' at the 

 proper page and plate (p. 87, pi. iv. figs. 1 & 2), I am prepared 

 to present a few remarks upon the pterylosis of the Caprimulgine 

 birds in my hands. 



