198 



Order ARTIODACTYLA 



KEY FOR SKULLS OF THE ARTIODACTYLA 

 (Domestic species included) 



1. Each eye socket incompletely encircled by bone, fig. 107a; 



upper jaw with incisors pig, Sus scrofa 



Each eye socket completely encircled by bone, fig. 107^; up- 

 per jaw without incisors 2 



2. Upper jaw with canine teeth, fig. 107^ 9 



Upper jaw without canine teeth 3 



3. Skull more than I2I/4 inches (313 mm.) long 4 



Skull less than I214 inches long 6 



4. Open space present between lacrymal and nasal bones, fig. 



107^ elk, Cervus canadensis 



Fig. 107. — Characters used in the identification of ungulates: 

 a, skull of pig, side view; b, skull of American elk, side view, but 

 without lower jaw. 



