w 





306 



MOXOGRAPUS OP NORTH AMERICAN RODENTIA. 



The general mcasuretneiits 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 beeo 

 could they have been made from fresh specimens and by a single person.* 

 They arc in the main, however, borne out by the measurements of the skulls. 

 The material, bein^ 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. vtrginianus. 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 jjelage. The average length of the body is IG 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 froln 2.25 to d.OO. Hence the average length of 

 the body is about an inch and a quarter less than in the Massacimsetts series 

 (bce 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. 

 Eichardson 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.G7 and 1.45. The difference between the average of tliis 

 series and that of another series of fourteen specimens from Oxford County, 



* lu aU tbu oriKiuul uieaHurementii given in thin paper, the dimeDsioui) uro tbo diataoces in a 

 straigbt line between tbc exireialties of tbo parts nieaHured, and are bence less tban if measured over 

 tbe convexities of tbe xarfoce, a» ia often done. Tbe belgbt of tbe ear is taken b; measuring from tbe 

 inner boae of tbe ear to the tip, instead of either from tbe anterior or poiterior base, and is benco ratber 

 less than it would be by eitber of tbe otiiei methods. 



