LAGOMYIDA—LAGOMYS—GEOGRAPHICAL DISTRIBUTION. 409 
Length about 7.00, ranging in adult specimens from 6.50 to nearly 8.00. 
Ears broad, large, and rounded. Hind foot generally about 1.15 to 1.25 in 
adults; fore foot about 0.80. The black naked pads at the base of the toes 
are yery prominent. 
The skull ranges in length from about 1.70 to 1.88; breadth, 0.82 to 
0.92; interorbital breadth, 0.21 to 0.25; average length of the nasals about 
0 62, narrowing posteriorly from about 0.25 to 0.18. Lower jaw, length, 
1.07 to 1.25; height 0.57 to 0.70. The series of skulls show a considerable 
range of variation in size in adult specimens. The bones of the skull are 
thin and papery, and often the parietal suture remains unclosed in fully 
adult skulls, and the cranial elements of the skull are never to any great 
extent ankylosed. The nasal bones, however, finally become firmly united. 
The specimens on which the present article is based were all taken on 
the Snowy range, in Park County, Colorado, and all but two at one locality. 
The measurements of the animal were all taken in the field by myself, from 
fresh specimens. 
GEOGRAPHICAL DISTRIBUTION. 
The North American Pika inhabits the summits of the Rocky Mount- 
ains from Colorado far northward into British America. It is also found 
near the summit of the Wahsatch range in Utah, the Sierra Nevada in 
California, and the Cascade Mountains in Oregon. I found it very abundant 
near the limit of trees in the vicinity of Montgomery, Park County, Colorado,* 
and Lieut. W. L. Carpenter has collected it at other neighboring points of the 
Snowy Range. Dr. J. G. Cooper found it near the limit of perpetual snow in 
the Sierra Nevada,t where he reports it as quite common over a limited 
district; while Professor Gabb met with it as far south as the northern 
boundary of Lower California (lat. 32°), at an altitude of about 10,000 feet.t 
Mr. J. K. Lord met with it (his “ Lagomys minimus”) near the summits of 
the Cascade Mountains at an altitude of about 7,0C0 feet above sea-level, 
and also at Chilokweyuk Lake, on the western slope of the Cascades |] — Dr. 
* Ball. Essex Institute, vol. vi, pp. 56, 66. 
t Proc. Cal. Acad. Nat. Sci. vol. iii, p. 69; ib., 1868, p.6. 
¢ Proc. Acad. Nat. Sci. Philad., 1868, 2. 
§ The characters Mr. Lord gives for his “ Lagomys minimus” do not indicate any specific difference 
while the habits he attributes to it are exactly those of the L. princeps as recorded by a number of 
independent observers. He recognized L. princeps as occurring near the same locality; but, beeause he 
saw no evidence of L. princeps carrying leaves and grass into its warrens, he regarded the animals seen at 
the two neighboring localities as distinct species. His ‘ Fiber osoyoosensis”, described in the same paper, 
rests on similar mistaken assumptions. 
|| Proe. Zodl. Soc. Lond., 1863, pp. 96, 97. 
