248 



STRUCTURE AND CLASSIFICATION OF BIRDS 



are in Bubo, where, as already explained, they are thin 

 plates, hardly thicker than a piece of paper. So far Photo- 

 dilus agrees with Strix ; but there are points in which the 

 skull of this aberrant owl is nearer to the bubonine section 

 of the order. It has not the occipital convexities which are 

 so striking a feature of the skull of Strix. Finally Pliotodiliis 

 is strigine in the non-extension over the occcipital region of 

 the temporal fossse, which do so extend in many of the 

 Bubonidae. In Strix there is but one notch on either side 



FIG. 126. SKULLS OF Strix (LEFT-HAND FIGUEE) AND Bubo 



(AFTER BEDIMED). 

 E, prefrontal process ; W, maxillo-palatines. 



of the sternum ; in other owls, including Photodilus, there 

 are two. The vomer of the owls is not large, 1 and behind it 

 there is a medio-palatine, at least occasionally present. 



The lacrymals, like the maxillo-palatines, with which 

 they come into contact, are swollen and spongy. The 

 nostrils are often partly covered by ossified alinasals, and 

 there is a largely bony internasal septum. 



1 Said by SHUFELDT to be absent in Speotyto. 



