MOEPHOLORY OF THE OWLS. 227 



Thus, Stjrnia, Carine, Speotyto * are placed in the Bubonlnce, to wliich I do not think 

 they rightly belong, whilst Aslo, Sijniium, and Nyckda probably represent as many 

 sub-families. 



Dr. Gadow (2-4) accepts Nitzsch's diagnoses of the general pterylography of the Owls. 

 In one point, however, he is confident where Nitzsch wavered, inasmuch as he states 

 that down-fpathers occur and are confined to the apteria. Nitzsch was doubtful on this 

 point, but observed that he had never fou]id them when he searched for them. As a 

 matter of fact, they occur only in ih.o, pt. ularis (PL 24, d.f.). 



In the structure of the neossoptiles Gadow considers the Owls to approach the Goat- 

 suckers. He remarks that they are double as long as the neossoptiles of the Accipitres, 

 and are further cliaracterized by their extreme softness (" weichlieit "). As will be pointed 

 out later (p. 253), the " nestling-down " of the Accipitres is of two kinds — one pi-eceding 

 the future definitive contour-feather, and one preceding tlie future definitive down-feather ; 

 and it is probably with this last that the " nestling-down " featlier of the Owl has been 

 compared, instead of with the former, with \^■llich it really corresponds. 



Moulting takes place once annually, in July and August. 



Although the curious separation of the external aperture of the asymmetrical ears of 

 Aslo into two chambers (p. 259) is briefly described, no mention is made of the " oper- 

 culum " or of the posterior membranous fold fencing in this aj^jcrture from behind. 



Meijere, in his papers on the distribution of the hair in the Mammalia (9) and of the 

 feathers amongst Birds (10), has brought to light some most interesting and valuable 

 facts. In his first paper he sets himself the task of proving that there is considerable 

 evidence to show that the arrangement of the Mammalian hair indicates the presence of 

 an earlier clothing of scales f . On the loss of the scales the hairs remain, and thus is 

 explained their peculiar distribution in groups of three or more, as the case may be. 



The author, in bis second paper (10), points out the close similarity in the arrange- 

 ment between hairs and feathers, and remarks that, though he does not wish to imply an 

 homology between these structures, yet their close resemblance in this particular would 

 be a not unimportant argviment in favour of such homology if it were supported by other 

 evidence. But our knowledge on this point is as yet very meagre. 



According to Meijere, at a certain stage in the development of the Avian type the 

 liody-clothing consisted of alternating groups of similar feathers, whose long shaft bore a 

 biserial system of branches — Rami. These, in their turn, supported a biserial system of 

 smaller branches — Radii. The latter consisted of a row of cells, provided distally with 

 a pair of fila (" wimperchen"), which probably here and there took the form of booklets. 

 Later, the middle feather of each group developed at the expense of the rest, which now 

 assumed the form of the diminutive feathers which we know as Filoplumes. The middle 



* I am only takiug into account such genera as I have had the opportunity of studying ; Hetero'jlaux and Gi/ninasio 

 have not yet come under my ken. 



t The nature of the combined covering of scales and hairs can bo studied on the scaly tails of such animals as 

 Mas decumanus. Here they arise in groups of three from behind each scale, the middle one being the strongest. In 

 some cases the number of hairs associated with each scale is greater than three. In Castor fiber, for instance, there 

 are eight such hairs. In cases of this kind the hairs seem aU to be of equal calibre. 



