224 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



In the above-described specimens the hairs of the yellowish areas 

 are somewhat paler on the tips, light plumbeous at base, and wavy. 

 The longest hairs of the mane, in the male, measure 120. mm. in 

 length. They are broadly white at base, succeeded by reddish brown 

 and a narrow annulus of yellowish white, pointed with black. In 

 the white areas the hairs are white to the base. 



A male fetus (No. |||ff U.S.N.M.) that would soon have been 

 born, removed from its mother (No. 1889, Collection International 

 Boundary Com.) June 15, 1892, is grayish buff, finely lined with 

 black, slightly stained with russet on the head and rump, which 

 latter is white only in two lateral spots. A large white spot occupies 

 the forehead. There is some black on the edges of the ear, the end 

 of the muzzle is black, and there is a small black spot above each 

 eye. The hoofs are black, tipped with horn color, with reddish hair 

 growing around the base. Underparts buffy, liberally sprinkled with 

 white hairs in the middle. The white areas on the underside of the 

 neck and the triangular black sex mark on the sides of the head are 

 plainly indicated. 



An albino antelope was seen by many persons between the Verde 

 Valley and Whipple Barracks, Arizona, in 1885, and was not known 

 to have been killed up to the time of my departure in 1888. 



Young a few weeks after birth are paler than adults, without the 

 distinct rump patch of white, this part being overlaid with pale 

 russet ; and all of the pattern is obscure, the white areas being stained 

 with dull buff, and the areas which are blackish in adults but f aintlv 

 indicated. A curl of dusky hair over the frontal bone, on each side, 

 indicates the location of the coming horns of the male. 



Molting period. — We killed the first Mexican antelopes on the 

 boundary in the desert region between the Rio Grande and Mimbres 

 valleys, late in March, 1892. At that season they were beginning to 

 shed about the face. A male killed between the Mimbres Valley and 

 the Upper Corner (Monument No. 40), April 29, had received the 

 summer coating on about one-half of the head. By the end of May, 

 all of the old males had shed the winter hair from all of the head, 

 and, in some cases, from large areas of the body. An old male, killed 

 in the Animas Valley, New Mexico, July 6, was in full summer coat ; 

 but not all of the antelopes had changed by that date. 



Cranial characters. — The skull (fig. 33) differs from that of amcri- 

 cana in having the orbits less abruptly protruding antero-inferiorly, 

 and the premaxillaries more slender posteriorly ; audital bullte thin-- 

 ner ; lips of posterior nares longer. 



Horns. — In females the horns are sometimes absent or abortive, 

 occasionally quite large ; but the horns of adult males are invariably 

 much larger than those of females. These appendages are essentially 



