394 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
localities south of the Mexican boundary. To the westward it ranges to 
the Pacific, from California northward to Alaska, and doubtless extends 
northward to the limit of trees. It is extremely abundant in the wooded 
mountainous portions of Colorado, where, as I am informed by Dr. Coues, 
who speaks from reports given him on the spot, it sometimes becomes a con- 
siderable article of diet. The same naturalist also found it no less numer- 
ous in the Sweetgrass Hills, or “Three Buttes” of Northern Montana, where 
numerous individuals were secured. Though chiefly a woodland animal, it 
is not seldom seen ranging the prairie many miles from the nearest timber— 
perhaps traveling from one feeding ground to another. 
TaBLE I.—Measurements of seventeen skulls of ERETHIZON DORSATUS var. DORSATUS. 
3 [a Nhe 
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g | 2 Locality. eo. |e Ce E 2 E e |e 2 "bp| oF A 3 Remarks. 
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2] io ° i — & s Ss aS Ra) As ° ° 
(NS nm) A o A A A A |p i=) p H H 
: —— 2 
2356 ..| Essex County,N.Y.|..-.| 3.95 | 2.65 | 1.03 | 1.30 | 0.52 | 0.77 | 1.25 | 1.90 | 1.00 | 2.70 | 1.40 Very old. 
SUH hase Paced Olpecsempeedess |.---| 4.15 | 2.80 | 1.20 | 1.20 | 0.63 | 0.77 | 1.45 | 2.30 | 1.10 | 2.95 | 1.40 =e dO; 
676 |....| Pennsylvania. -... |. -..| 3.59 2.50 | 1.00 | 1.20 | 0.52 | 0. 67 | 1.12) 1.85 | 0.97 | 2. 63 | 1.20 | Middle-aged. 
*819 |....| Norway, Me ...... .---| 4.25 | 2.90 | 1.25 | 1.32 | 0.70 | 0.85 | 1.50 | 2.37 | 1.00 | 3.05] 1.50] Very old. 
*820 |....| Umbagog Lake, Me}....| 3.90 | 2.80 | 1.46 | 1.33 | 0.72 | 0.75 | 1.25 | 2.00 | 1.00 | 2.75 | 1.20 Middle-aged. 
MBQL oo. ||- OO! fonsceeicc sae .-..{| 3.40 | 2.60 | 1.17 | 1.15 | 0.60 | 0.70 | 1.00 | 1.72} 1.02] 2.47] 1.30 | Rather young. 
RBS Seal aa Ovacaet= serccsein Rea PoaOOM eine 1.00 | 1.10 | 0.65 | 0.70 | 1.22 | 1.95 | 1.00 | 2.65 | 1.25 |-.--do. 
*823/|....| Upton, Me ........ ..-.| 3.40 | 2.35 | 1.10 | 1.08 | 0.60 | 0.74 | 1.12 | 1.67] 0.93 | 2.45 | 1.23 |.-..do. 
wp) Berl eset inpesemoc ses Q | 3.52 | 2.57 | 1.12 | 1.06 | 0.62 | 0.70 | 1.10 | 1.73 | 0.93 | 2.55] 1.18] Rather young; 
first molar just 
in sight. 
SEP nel beact CY bosmccomaieis Q | 3.65 | 2.50 | 1.10 | 1.13 | 0.58 | 0.68 1.10 | 1.83 | 1.03 | 2.75 | 1.20 }....do. 
WPA) | Peed cshil) neeescooseosis | 3.80 | 2.70 | 1.25 | 1.20 | 0.60 | 0.80 | 1.30 | 2.05 | 0.97 | 2.80 | 1.35 | Middle-aged. 
BROT ata |p OR ae le 3.75 | 2.78 | 1.07 | 1.12 | 0.67 | 0.75 | 1.25 | 2.03 | 1.03 | 2.80 | 1.33 |...2do. 
wert} heer) eset secesocaccos |e 3.65 | 2.70 | 1.10 | 1.20 | 0.60 | 0.70) 1. 1.95 | 0.97 | 2.65 | 1.35 |....do. 
*B15 |... | Norway, Me...-... ---.| 3.90 | 2.60 | 0.85 | 1.23 | 0.50 | 0.70 | 1.40 | 2.05 | 0.98 | 3.00 | 1.33 | Very old. 
*816 |....|.---dO ....-....---.|..-.| 3.95 | 2.70 | 1.08 | 1.22 | 0.72 | 0.82 | 1.37 | 2.05 | 1.06 | 2.90] 1.35 ]|....do. 
*813 |....| Upton, Me.-...-.. o& | 4.25 | 3.00 | 1.25 | 1.27 | 0.73 | 0.73 | 1.57 | 2.30 | 1.12 | 3.03:) 1.35 | .-..do. 
R657 [Sooo | eave Oivesnece cas eae co | 4.25 | 2.85 | 1.10 | 1.50 | 0.75 | 0.95 | 1.62 | 2.50 | 1.10 | 3.20] 1.45] ...-do. 
* In the Museum of Comparative Zodlogy, Cambridge, Mass. 
t From front edge of the intermaxillaries to the occipital condyles. 
