No. I.] THE CRANIUM IN THE OWLS. 131 



Finally, it may be said that the mandible is markedly wid- 

 ened beneath the ramal vacuity; that th.Q pars planes of the 

 mesethmoid are thick and swollen at their apices, and widely 

 spread out ; that the palatine bones are narrow, and the vomer 

 well developed and mesially swelled ; and, lastly, the large 

 orbital wings of the alisphenoid are so long that they almost 

 reach the linear os jugale. 



Taking into consideration the depression of the cranium, its 

 small orbits, and the marked development of the diploic tissue 

 in all the bones, Strix flammea, of all the North-European spe- 

 cies of owls, stands nearest to Syrnium lapporiiciim ^ though in 

 the latter the interorbital septum is very far from being as 

 thick as in Strix flammea, and the lateral processes of the 

 ethmoid are not swollen at all. 



Upon the whole, then, when taking into account the struc- 

 ture of the cranium in Strix flammea, although this exhibits no 

 asymmetry, this form occupies an isolated place among the 

 owls, and these peculiarities of its cranium, when taken in 

 connection with the characters obtained from the structure of 

 the sternum, znd ftircula, doubtless contribute towards sustain- 

 ing the opinion of placing this form in a separate sub- 

 family. 



As far as the auricular openings in Strix flammea are con- 

 cerned, they are small or of medium size, and probably sym- 

 metrical (or very little asymmetrical). The ear-flaps, which 

 are both superiorly and inferiorly squarely truncated, and are 

 about as broad as they are high, give them, upon the whole, 

 a resemblance to the right ear-flap in the Syrnium, group ; on 

 the other hand, these ear-flaps are larger than the apertures 

 they are intended to cover, and consequently they overlay the 

 auricular margins. Further, we observe the characteristic long 

 and broad fold of skin, overgrown with stiff feathers (the veil), 

 which stretches, as an oblong semi-arc, from the base of the 

 superior mandible above the eyes, down behind the ear-open- 

 ing upon either side, from thence quite out to the symphysis 

 of the lower jaw. This fold of skin corresponds to the verti- 

 cal fold that surrounds, posteriorly, the slit-like ear-opening in 

 the genus Asio. 



