252 STRUCTURE AND CLASSIFICATION OF BIRDS 



seen from the figure, the bronchial rings in front of this 

 attachment are complete rings, with no membranous inter- 

 space left. In Strix, on the other hand, and in Buho and 

 Syrnium, the intrinsic muscles are inserted on to the first 

 bronchial semi-ring. In Asio seven complete rings intervene 

 between the bifurcation of the trachea and the first incom- 

 plete bronchial semi-ring, to which the muscles are attached. 

 In Photodilus the intrinsic muscles are inserted on to the 

 second bronchial semi-ring. 



Until lately the owls have been almost invariably placed 

 in the immediate neighbourhood of the diurnal birds of prey. 

 Latterly, however, the opinion has been gaining, ground that 

 it is to the picarian birds (in a wide sense) that they are most 

 nearly allied. This opinion, more than hinted at by Gareod 

 and Newton, has been given a practical, shape in theclassi- 

 fications of Furbeinger and Gadow. The latter has in- 

 geniously pointed out that it is impossible to imagine that 

 the Striges have been derived from the Accipitres, since, 

 although without an ambiens, they have much the same 

 structure of foot as the Accipitres with an ambiens. Hence 

 it is difficult to believe that they would have lost it ; he con- 

 cludes ' that they are derived from some bird without an 

 ambiens, and the failure of Mitchell to find the last trace 

 of the missing ambiens — obvious in some birds which are 

 clearly the descendants of birds with an ambiens — still 

 further supports that way of looking at the matter. Even 

 in the skull, where the principal likenesses between the 

 Accipitres diurnse and nocturnsB (as the two groups in 

 question have been called) have been seen, there are really 

 many differences. It is only, for example, in the skulls of 

 those Accipitres to which the owls have been supposed to 

 have the least resemblance, i.e. the Cathartidse and Serpen- 

 tariidse, that there are basipterygoid processes. The owls 

 are decidedly not desmognathous (in the sense of a maxillo- 

 palatine union), and their lacrymal is quite different from 

 that of the hawks and eagles. The palate, too, is incom- 

 plete in front of the maxillo-palatines, not solid, as in the 

 Accipitres. As to other anatomical features, it is harder to 



