MAMMALS OF THE MEXICAN BOUNDARY. 257 



been worn away ; tail, viewed beneath, gray centrally, bordered with 

 black, succeeded by grayish white, and gray all round at base; the 

 black lateral stripes beginning narrowly, and gradually encroaching 

 on the gray central stripes until the latter becomes obliterated at the 

 extremity, which is nearly all black; the 5-striped' pattern of the 

 tail is less distinct above, and the central area is reddish. The 

 slightly developed ear-tufts are dusky, and the long, full whiskers 

 jet black. It has four pairs of mammae. Length, 375 mm. ; tail 

 vertebrse, 140; tail to end of hairs, 185; hind foot, 55; ear from 

 crown, 21; ear from notch, 30; length of head, 56-; distance from 

 nose to eye, 25 ; to ear, 45. Skull, 50 by 29 mm. 



Cranial and dental characters. — In common with other members of 

 the subgenus Tamiasciurus, the dental formula is «j5j; pm^^; m|^|= 

 jjj=22, a minute and functionless premolar being present in nine of 

 the thirteen skulls examined. This form has the largest skull of any 

 of the known members of the subgenus Tamiasciurus. 



Life history. — To the naturalist, the meeting of a strange animal 

 in its native haunts is attended by a thrill of enthusiastic delight, 

 but my introduction to this beautiful squirrel was under circum- 

 stances lending added piquancy to the episode. In October of 1884 

 I accompanied, as medical officer, a small command of cavalry under 

 the leadership of Gen. George Crook. It was my first experience of 

 crossing the cordilleras of this subtropical region. The scorched and 

 barren plains of the low country, the broad reaches of grassy mesas, 

 and the difficult slopes bestrewn with scoria, lay behind us; and we 

 were traversing a fairly good mountain road at the summit of the 

 Mogollon Range, in central Arizona. The previous day's ride had 

 carried us well up into the belt of pine timber, and at night we had 

 encamped in a canyon where the first spruce trees were seen. I rode 

 out of camp next morning with my usual weapon, but with one com- 

 partment of my shooting vest filled with shells, which were carefully 

 loaded with buckshot. A flock of Mexican turkeys first engaged my 

 attention, and then a succession of new and strange birds and 

 mammals, until my saddle pockets were distended with specimens. 

 Then, belated as usual, I followed the trail of the command, which 

 lay along the summit of the mountain divide, whence one looked 

 down upon the undulating surface of Tonto Basin from the verge 

 of a sheer precipice on one hand, while upon the opposite side was a 

 gentle slope of heavily wooded country, in which a series of tortuous 

 ravines arise, which converge, deepening in their course, to unite far 

 below and 'form vast canyons. But the ravines alluded to had a 

 special flora of their own. Their shady slopes were covered with 

 large spruces and various deciduous trees, together with a luxuriant 

 30639—^0. 56—07 M 17 



