MOEPHOLOGY OF THE OWLS. 265 



studied. It is probable, as I liave pointed out in an eaiiier part of this paper, that 

 " pre-pennae " only are present in the young Owl, and that the " pre-plumulge " are not 

 represented in the very young nestling. When one reflects on the gi-eat range of grada- 

 tion in complexity of structure that obtains in the pre-pennae of different groups, from 

 the highly complex featliers of the Tinairiou, through the less complex feathers of the 

 GalIiform.es and Anserufonnes to the exceedingly simple hair-like structures of tlie 

 Columhce, it is pretty obvious that a great deal of work yet remains to be done before 

 this study is exhausted. 



JS'itzsch was apjoarently the first to notice the twofold nature of the neossoptiles. He 

 wrote concerning the " nest-plumage of Diurnal Raptorial Birds " that it " consists as 

 usual of downy barbs which are attached to the first perfect barbs of all the contour • 

 feathers, even the remigcs and rectrices, and disappear as the bird becomes fledged . 

 Moreover, the whole body, with tlie exception of the axillary cavity and lateral neck- 

 spaces, is covered with true permanent down-feathers, which bear no evanescent tips.' 

 In this last point, that the absence of " evanescent tips " to the feathers in question 

 proved them to be permanent down-feathers, he is evidently mistaken, inasmuch as they 

 are quite distinguishable from the defioitiv(; down-feathers, as was pointed out in the 

 earlier part of this paper. 



Dr. Gadow has stated that down-feathers occur on the nestling wherever they are 

 found on the adult. This is certainly not the case in the Common Duck, and there are 

 probably mauy other exceptions. 



The position of the femoro-crural band, which is peculiarly well developed in the 

 Owls, if it is not confined to this group, was a point upon which I was for a time inclined 

 to place considerable hope, and even yet it may prove of no little value to the often hard- 

 pressed taxonomist. For the moment, however, with me its trustworthiness is under 

 a cloud. The point, it must be remarked, is to note whether its outer end terminates 

 above or below the knee. After examining a considerable number of spirit-specimens 

 with regard to this point, an uncomfortable suspicion crossed me tliat this might dej)end 

 upon the position of the legs when finally fixed by the liardening influence of the spirit : 

 that is to say, it may depend upon the amount of rotation of the femur towards the 

 spine, since the skin in this region seems to have a certain amount of " play," in Avhich 

 case, of course, this band might appear to terminate a little above or a little below the 

 knee, just as this was near to or far from the vertebral column. Certainly the rather 

 large series of Asio accipltrinus all agree in having this band terminate at the knee- 

 joint ; in Bubo it appears to terminate below the knee, and in Carine very much below 

 this region. It was over this very species, however, that my faith received its first 

 shock, inasmuch as in a second example of C. noctua, which I examined before placing 

 it in spii'it, i was able to move the distal end of this tract slightly up or down at will. 

 The amount was slight, but still appreciable ; of course my test may be at fault, as I 

 pushed the leg upwards and the skin downwards at the same time. Now this particular 

 specimen had been dead some days, so tliat the delicate attachments may a'l have broken 

 away directly my somewhat rough experiment was begun; it is to be hoped that someone 

 will try to settle this point soon. 



36* 



