266 MR. W. p. PYCRAFT ON THE 



A comparison between the pterylosis of the adult and the embryo could not be expected 

 to lead to any very startling contrasts ; nor does it. It is interesting to notice, however, 

 that in none of the embryos of Jsio which I have examined is there any trace of the 

 voluminous neck-folds of the adult, but tlie feather-rudiments are seen to closely invest 

 the neck, as in Strix Jlannnea. Again, the external aperture of the ear in this species is 

 marked by a shallow depression whose long axis is not more than twice that of the 

 longitudinal axis of the eyelid ; the opercular and postaural folds are not even hinted at. 

 In Strix flammea the operculum, as in Asio, does not appear till later in development ; 

 its peculiar four-sided form seems not to be assumed until after the development 

 of this fold. 



The branches of the interscapular fork in the embryo of Strix appear to be longer 

 than in the adult ; but since I have only had the opportunity of examining a single adult 

 specimen, little importance can be attached to this. Similarly the interscapular fork of 

 Carine hrama differed, and this time markedly, from what one would have expected, 

 inasmuch as its branches were of considerable length, and not, as in the adult of C. noctua, 

 short and barely perceptible. This may mean one of three things : (1) the embryo is not 

 that of C. brama ; (2) that C. hrama may not belong to the genus Carine, but some other 

 genus of the Btihonidcc ; or (3) that this may represent an earlier stage in the history of 

 the development of this region of the tract. 



In all the embryos there was a distinct claw both on the pollex and index digits. The 

 form of the beak in all the embryos agreed with that of the embryo and adult of Strix in 

 being relatively long and straight, and contrasted with the short curved beak of the 

 embryo of Falco or of the adult Owls of the Asionid group. 



We come now to a question of wider and therefore of more general interest — the 

 nature of the evidence that a study of the Pterylography of the Owls affords as to their 

 systematic position. 



Nitzsch (13) years ago, approaching the subject from this point of view, came to the 

 conclusion that they were most nearly related to the Accipitres. They formed his 

 Aecipitrin(B nocturnce. He tells us that " there are two points which essentially distin- 

 guish this group pterylogra])hically from the preceding (Accijritres dkirnce), namely, the 

 constant absence of the aftershaft and the tcant of the circlet of feathers at the apex of 

 the oil-gland.'" And, further, " In their form the tracts agree in general with those of 

 the Ealcons, although they present noticeable differences. Among these the chief is that 

 in the Owls the region of the throat betAveen the rami of the lower mandible is never 

 continuously feathered, but the inferior tract issues from the angle of the gonys in the 

 form of a narrow band, and divides on the middle of the neck or close to the front of the 



furcula " The ^;/?<?r//^rt»mfr«^zs agreed, he found, very closely with that of C/rCM«. 



The pt. spinalis, " although arranged in accordance with the principal type of the Ealcons, 

 presents this difference — the two arms of the dorsal portion which run to the fork of the 

 scapular portion consist, pi-obably ahvays, of two rows of feathers." 



As the present paper show^s, his description of the interi'amal area must be taken as 

 the exception, not the rule. Por the rest, one may adopt the auditor's formula, save in 

 one or two minor details — " examined and found correct." 



