MAMMALS OF THE MEXICAN BOUNDARY. 



195 



Fie; 23.— Odocoileus HEMroNus canus. El Paso, Texas. 

 (Cat. No. 63144, U.S.N.M.) 



■white. A large ovate spot, occupying nearly the whole forehead, is 

 dusky from a liberal admixture of black hairs ; along its outer border 

 this spot becomes nearly black. There is a black area adjoining the 

 nasal pad, which is pro- 

 longed backward along 

 the upper lip, becom- 

 ing obsolete at the an- 

 gle of the mouth and 

 indistinct across the 

 lower ja-w. Tufts, of 

 yellowish brown hair 

 mark the placfes where 

 the horns are to appear. The outer surface of the ears is blackish 

 along the border terminally ; there is a dusky spot on lower border of 

 inside of the ear and a blackish spot between the ears. The chest and 



breast are dark fuliginous. 

 Abdomen, inguinal region, 

 buttocks, and basal portion 

 of tail pure white. The 

 animal was molting and the 

 white spots rapidly disap- 

 pearing. Hunters informed 

 me that the spotted coat in 

 fawns of the mule deer 

 lasts but a few weeks. 



Skull and teeth.— Gora- 

 pared with the white-tailed 

 deeT of the Odocoileus 

 americamis group, which 

 includes 0. texanus and 0. 

 couesi of the present work, 

 skulls of the members of the 

 mule-deer group have the 

 brain-case low and flat- 

 tened (fig. 23). The pos- 

 terior facets of the occipital 

 condyles are concave in- 

 ternally instead of straight 

 or convex. The lachrymal 

 fossa is large and very 

 deep. The vomer is fused to the basisphenoid instead of hanging 

 free (fig. 19a). The premaxillary very rarely articulates with the 

 nasal bone, being intercepted by a broad process of the maxilla. The 

 mandibular ramus is more nearly vertical. The lateral teeth (fig. 



wM/i^ 



Fig. 24.— Teeth of Odocoileus hemionhs canus. (Cat. 

 No. 63144, U.S.N.M.) a," Profile of bight upper molak 

 series; b, crowns of eight upper molar series; c, 

 profile of right lower molar series; d, crowns of 



RIGHT LOWER MOLAR SERIES; C, INCISOR-CANINE SERIES, 

 FRONT VIEW. 



