STRIGES 



247. 



/ 



\ 



The colic caeca are always (fig. 125) dilated at the blind 

 end. The liver lobes are subequal, and the gall bladder 

 appears to be always present.* 



The skull of the owls ^ shows some differences in Strix 

 from the characters which distinguish the majority of the 

 group. 



In Strix the skull is elongate, the proportions being in 

 Strix flammea 66 length : 36 _ _ 



breadth. In another species 

 {Strix sp. inc.) 62 : 37-5. 



On the other hand in other 

 owls the differences betwee 

 breadth and length show gr 

 dually progressive series, ci 

 minating in Speotyto cunia 

 laria, in which the proportioi 

 are nearly equal, viz. 38 : 3 1 . 

 The skull of Strix further 

 differs from that of other owls 

 in the swollen character of 

 the prefrontal processes, 

 which are thin, almost paper- 

 like sheets of bone in other 

 owls. The interorbital septum 

 of Strix is thick, while in the 

 remaining genera it is reduced 

 to a thin dividing lamina, as is 

 the case with most birds. The 

 skull characters of the genus 

 Photodilus are to some extent 

 intermediate between Strix and the remaining genera of the 

 Striges. The interorbital septum of Photodilus is not 

 so thick as in Strix, but, on the other hand, not so thin as in 

 other owls, as, for example, Bubo. The prefrontals, although 

 not so swollen as in Strix, are not nearly so flattened as they 



Fig. 125. — Colic Cmox of Photodilus 

 (after Beudard). 



' Absent in Speotyto ; cf. Shufeldt, ' Notes on the Anatomy of Speotyto' 

 Journ. Morph. iii. 1889, p. 122. 



'' See for certain details of skull structure Pakkeb, Linn. Trans. (2), i. p. 138. 



