6. Skull about eighteen inches long, with large upper canines; space from 



front of jaw to tip of nasals less than one-fourth the total length of 

 the skull 



Cervus Elk or Wapiti 

 Skull smaller, without above combination of characters; canines, if pres' 

 ent, very small 7. 



7. Skull about fifteen inches long; small upper canines often present; with 



antlers or stubs in both sexes; tip of nasals above first cheek teeth 

 Rangifer Caribou 

 Skull not over twelve inches long; upper canines rare; tip of nasals not as 

 far back as first cheek teeth 8. 



8. Frontal bone with a fairly even margin over orbit 9. 

 Frontal bone with a definite notch or notches over front part of orbit 10. 



9. Orbit circular; horn, if present, rising almost vertically above most of 



orbit; lacrimal bone without depression on outer face 

 Antilocapra Prpnghorn 

 Orbit slightly longer than high; antlers, if present, rising behind orbit 

 almost parallel wath the frontal; lacrimal with a definite hollow on 

 outer surface 



OdocoUens White-tailed and Black-tailed Deer 



10. Horn cores circular in cross section; frontal region flat or concave be- 



tween orbits; nasals not extending as far back as level of front of orbits 

 Oreamnos Mountain Goat 

 Horn cores, when present, triangular or long-oval in cross section; frontal 

 definitely convex between orbits; nasals extending as far back as orbits 



11. 



11. Marked depression on face of lacrimal; nasal convex; little or no gap be- 



tween lacrimal and nasal; anterior slope of skull about twice as long 

 as the posterior slope; horn triangular at base 



Ovis Sheep 

 No depression on face of lacrimal; nasal concave posteriorly; large gap 

 between lacrimal and nasal; anterior slope of skull about as long as 

 posterior slope ; horn long-oval at base 



Capra Goat 



12. Skull six to twelve inches long; back of cranium high and squared ofi^; 



canine teeth present, molars with several cusps 13. 



Without the above combination of characters 14. 



13. Six upper incisors; upper canines extending sideways 



Sus Pig 

 Four upper incisors; upper canines directed downward; a deep notch in 

 side of upper jaw to receive lower canine 

 Pecari Peccary 



14. Skull about two feet long; cheek teeth almost square and with complex 



folds of enamel shown on grinding surface 

 Equus Horse 

 Rarely more than twelve inches long 15. 



15. Canine teeth present 16. 

 No canines; a wide gap between incisors and cheek teeth (Rodents) 57. 



525 



