36 ME. W. P. PYCEAFT ON THE 



inasmucli as the latter, apart from its larger size, has a relatively deeper post-cavernum 

 overshadowed by a prominent tubercular swelling, a relatively larger postorbital 

 process, crescentic instead of spatnlar in form, and supporting a relatively larger post- 

 orbital tubercle which lies nearer the middle of the process ; besides the vomer and 

 posterior ends of the palatines are fused as in the Strigidae. The inetasternum. is broader 

 and the external pair of notches wider than in A. acciintrinus ; and in the pelvis, the 

 dorsal plane is wider and projects further forwards, relatively. In the foot Ph. 1, 2 of 

 D. II are indistinguishably fused, but free in A. acciintrinus ; whilst the furculahas the 

 limbs nearer together and the median apophysis marked by a distinct ventralward 

 flexvire, which is wanting in A. accixtitrinus. 



The skulls of Strix, Asio, and Photodilus, when compared with regard to the tympanic 

 cavity, prove extremely interesting, forming a series increasing in complexity, from Strix, 

 through Photodilus, to Asio. The nature of the modifications can be studied in the 

 Pi. 2. tigs. 2, 3, 5. 



The skull of Photodihis is in many respects besides an interesting one. In the form 

 of its maxillo-palatine it is intermediate in type between the Strigidse and Asionidae. 

 It has the vestigial vomer of Ketupa ; the swollen antorbital and interorbital septum 

 of Stinx ; the lachrymal of the Asionidae ; the skull-roof of Syrnium, though less swollen 

 by pneumatic tissue ; a quite peculiar quadrate, inasmuch as its orbital process is 

 vestigial and recalls that of the Caprimulgi. 



The skeletons of the larger species of Athene and Glaucidium are very difficult to 

 distinguish, so much so that it is probable that a comparison of a large series w^ould 

 make it necessary to include both genera under one head. The small Glaucidiwm 

 ridgwayi — the only small member of the genus represented in our Collection — differs far 

 more from the larger members of the genus than the latter does from species of Athene 

 of similar size. 



The species included in the genus Syrnium require very careful study, judging from 

 the few skeletons in our collection. It is possible that besides Pulsatrix one or two 

 other forms wiU have to be redistributed. With regard to Pulsatrix it is interesting to 

 note that whilst in its pterylography it is distinctly Bubonine, in its skull and trunk- 

 skeleton it partakes of the characters which obtain in Syrnium, being indeed almost 

 halfway between »S^. uralense on the one hand, and Bubo on the other. S. uralense 

 undoubtedly belongs to the genus Syrnium, though its skull differs at first sight from that 

 of S. aluco. These differences, however, when examined, are only due to the exaggeration 

 of the characters seen in S. aluco. Syrnium selopiito is another peculiar form, inasmuch 

 as in its skull Bubonine characters are unmistakable, nevertheless Syrniiue features 

 predominate. The skuU of Ciccaba is truly Syrniine, but I have not had an opportunity 

 of examining Scotiapex in this particular. Prom the variability which obtains in the 

 skulls of Syrnium it would seem that the group was but recently derived from the 

 Buboninae, and that but few of the connecting-links have yet disappeared. This sub- 

 family will evidently repay much further research. 



The parieto-alisphenoid articulation which obtains in Ketupa, Bubo, Scops, Gymno- 

 scops, Syrnium, and apparently Strix also, may likewise be found in other genera when 



