306 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
The general measurements of the different varieties of Lepus americanus 
have been necessarily taken almost wholly from skins, and in part by differ- 
ent observers. They are hence less satisfactory than they would have been 
could they have been made from fresh specimens and by a single person.* 
They are in the main, however, borne out by the measurements of the skulls. 
The material, being similar in all cases, affords doubtless a tolerably fair 
means of determining the individual range of variation and the amount of 
variation with locality. Contrary to what usually happens, there is in this 
species apparently no increase in size to the northward, some of the largest 
specimens being from New York, Pennsylvania, and Massachusetts, and 
belong to var. virginianus. The specimens from Maine (see measurements 
of the skulls) scarcely differ from those from the Fur Countries, and the speci- 
mens from the Wind River Mountains (var. bairdi) fully equal those from 
the most northern points. 
In Table XV, the specimens are chiefly from very northern localities, 
and all in winter pelage. ‘The average length of the body is 16 inches, vary- 
ing from 15.25 to 17.10; length of hind foot 5.10, varying from 4.70 to 5.25; 
length of ear 2.70, varying from 2.25 to 3.00. Hence the average length of 
the body is about an inch and a quarter less than in the Massachusetts series 
(see below), while the difference in the hind foot and ear is less than one 
and a half tenths of an inch. The difference in length is more apparent than 
real, as the skins from Arctic America had never been filled, and are hence 
more contracted by drying than the others. The trifling difference in the 
size of other parts corresponds very nearly with that indicated by the 
skulls. According to Dr. Gilpin, Nova Scotia specimens range in length from 
17.00 to 20.70 inches, and a specimen from the Fur Countries, of which Dr. 
Richardson gives measurements, had a length of 19.00 inches. 
In Table XVI are given measurements of twenty-six skulls, mainly from 
the Mackenzie River district. Of these, the average length is 3.04 inches, 
the extremes being 2.30 and 2.87; the average breadth is 1.52 inches, the 
extremes being 1.67 and 1.45. The difference between the average of this 
series and that of another series of fourteen specimens from Oxford County, 
“Tn all the original measurements given in this paper, the dimensions are the distances in a 
straight line between the extremities of the parts measured, and are hence less than if measured over 
the convexities of the surface, as is often done. The height of the ear is taken by measuring from the 
inner base of the ear to the tip, instead of either from the anterior or posterior base, and is hence rather 
less than it would be by either of the other methods. 
