!P.<'lf. 



III. 49.— Skulls of Owls Showing the Asymmetry of the Skull of 

 Tengmalm's Owl, and the Curious Differences in the Form of the 

 Squamosal in the Young Tawny Owl (centre figures) and Young Burrow- 

 ing Owl (to left and below). 



27 



