No. I.] THE CRANIUM IN THE OWLS. 1 27 



to be less extensive, inasmuch as the orbits themselves are, 

 comparatively, not very large. 



Group V. Ear-flaps present. Cranium asymmetrical upon 

 right side. Auricular openings reniform in outline, and, 

 as in the case of the earflaps, largest upon the right side. 



a. Crania with slight asymmetry. 



8. Syrnium uralense (Pall.). 



Auricular openings wide, carried high up, with broad ear-flaps, with the 

 difference between the two flaps not as marked. Osseous crest on os 

 squamosum completely free above, more conspicuously bent forwards 

 upon the right than upon the left side, though without coming in contact 

 with the posterior surface of the alisphenoids in either case. Frontal 

 bones rounded at the posterior margins of the orbits, with a deep concavity 

 behind either supraorbital process. Longitudinal median furrow present 

 upon the superior aspect of the cranium, and the greatest height of the 

 latter is situated somewhat posterior to the middle of the orbital cavity. 

 Interorbital septum quite thick. Jugal linear. Vomer rudimentary. Supra- 

 occipital foramen absent. 



b. Cranium decidedly asymmetrical. 



9. Syrnium lapponicum (Hunt.). 



Ear-openings wide, slit high up, and with broad ear-flaps. Asymmetry 

 slight. Osseous crest on os squamosum normal on left side, conspicuously 

 individualized. Osseous crest on right side has its supero-external angle 

 inclined forwards and coossified with the posterior margin of the alisphe- 

 noid, which is strongly developed laterally. Frontal bones completely 

 rounded ofE at the posterior borders of the orbits, and with a profound 

 notch posterior to the supraorbital processes. Cranium with a longitudinal 

 median furrow on its superior aspect, and the greatest depth of the former 

 is posterior to the orbits. Interorbital septum short and thick ; orbital 

 diameter comparatively small. Jugal linear. Vomer rudimentary. Supra- 

 occipital foramen absent. 



The fifth group, which, as above noted, is closely related to 

 the fourth, and contains the two other North-European species 

 of Syniium, is characterized by having the cranium as well as 

 the auricular openings and ear-flaps asymmetrical. So far as 

 the two last-named parts are concerned, they have a structure 



