No. I.] THE CRANIUM IN THE OWLS. 149 



here the lateral borders are quite concave. Where the frontals 

 enter into the formation of the posterior peripheries of the 

 orbits their borders are rounded off ; and, if we view the skull 

 from behind, the supraorbital processes are concealed from 

 sight by the vertex of the cranium. 



The thinner (transparent) parts of the wall of the inter- 

 orbital septum are quite extensive. The osseous crest on 

 either squamosal bone is of medium size only. Above, it is 

 completely free, and there develops a curved process, directed 

 forwards and upwards, which, when the cranium is viewed 

 lateral-wise, is seen to be opposite to the posterior border of 

 the quadrate. Regarded from in front, it is only their outside 

 edges that become visible to the outer side of the large orbital 

 wings (that is, the osseous crests on the alisphenoids). An 

 extremely minute supraoccipital foramen pierces the supraoc- 

 cipital bone {sgjmjna occipitis), the diameter of which in the 

 subadult individuals is equal to about i mm., while in the older 

 birds it is barely more than ^ mm. 



Anterior to the basipterygoidal processes {proc. pteryg. oss. 

 sphenoid.) either pterygoid is compressed from above down- 

 wards, having a uniform width, and with its cultrate edge 

 directed anteriorly. The palatine bones are quite broad ; the 

 lateral processes of the os ethnioidcs pass outwards so as to be 

 about opposite the external margins of the palatines, when we 

 regard the cranium from beneath. Vomer is rudimentary, as 

 only its posterior moiety ossifies as a minute spicula of bone ; 

 ossification not being extended to its anterior end. It is very 

 likely that in still younger individuals it does not ossify at all. 

 The maxillo-palatines are of unusually large size and come 

 very near being in contact in the middle line, below. 



8. Syrnium uralense (Pall.), 1776. 



(Plate XVII, Figs. 15, 16; Text-fig. 4.) 



Auricular openings and their flaps asymmetrical, the cranium slightly 

 asymmetrical. 



The dermal parts of the auricular openings are of subequal 

 size, with a somewhat asymmetrical lid ; upon the whole, 



