196 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



24a-(Z) are very large, the premolars are relatively wider, and the 

 second and third premolars more deeply grooved internally than in 

 members of the americanus group ; and the incisors, notably the sec- 

 ond, are broader and the series more spreading (fig. 24e). 



The horns. — The members of the mule deer group are distinguished 

 by dichotomous horns. Variations in a selected series, from central 

 Arizona are shown in the table of measurements on pages 204 and 205, 

 to which the diagram below (fig. 25) relates. The subspecies canvs 

 differs from typical hemionus in having the antlers lighter and more 

 slender ; as in that form, the beam is short, and concave anteriorly In 

 j'oung bucks the horns begin during the first year as simple spikes, 

 which, when shed, are replaced by singly forked ones, whose successors 

 become more complex and compoundly dichotomous. The horns can 

 be detected beneath the skin before the spotted coat of the male fawn 

 has entirely disappeared. In central Arizona I saw a half-grown 



buck, still suckling, which had horns 

 just starting through the skin, on 

 December 29, 1885. 



In the high region of central Ari- 

 zona the mule deer carry their 

 horns throughout the month of Feb- 

 ruary. On April 11, 1887, I killed 

 an old buck that had recently shed 

 its aiitlers, at Pecks Lake, Upper 

 Fig. 25.-DIAGRAM of antlers of odocoi- Verde Valley, central Arizona. 

 LKus HEMIONUS CANU8. (For u.e of letter- Bucks killed in the Mogollou and 



iiig see tables on pp. 206-7. ) o -ri • • 



ban b rancisco mountains, June 1 to 

 20, 1887, had grown horns varying in length in different individuals 

 from 2 to about 10 inches. During August and September I saw small 

 herds in the mountains of central Arizona, composed entirely of old 

 bucks, carrying large heads of vascular antlers in full velvet. Two 

 bucks, killed November 9, 1885, on Ash Creek, Yavapai County, Ari- 

 zona, furnish my earliest record of horns entirely free from velvet. A 

 fine old buck, shot by Gen. George Crook at Mud Tanks, central Ari- 

 zona, October 2, 1884, had antlers which had become hardened and 

 nonvascular, but still retained their coating of velvet throughout. In 

 November the velvet finally disappears from the horns, except in the 

 abnormal males known to the frontiersmen as " cactus bucks." 



Among the abnormal horns of the mule deer I have seen the fol- 

 lowing: On August 20, 1887, Mr. MacFarland <■ brought a female 



"Mr. Andrew MacFarland, whose authority I shall frequently cite, guided 

 the expedition commanded by Lieut. A. W. Whipple from the Mississippi River 

 to the Pacific Ocean, by a route near the thirty-fifth parallel, when surveying a 

 railroad route to the Pacific in 1853 and 1854. 



