328 



Measurements of thirty-seven skulls o/Putokics vison. 



6530 

 8709 

 8797 

 8796 

 8707 

 8703 

 8702 

 8798 



-8648 

 8708 

 6531 

 8704 

 8706 

 8705 

 3284 

 43tJ9 

 813-3 

 4305 



12915 

 3730 

 3824 

 1169 

 3085 

 3084 

 3823 

 3822 

 2242 

 2243 

 2241 

 2244 

 2250 

 2267 

 1847 

 4834 

 4835 

 1894 



11315 



Locality. 



Fort Yukon, Alaska 



Alaska 



do 



do 



do 



do 



do 



do 



Alaska (Kadiak) 



Alaska 



do 



, do 



do 



do 



ITelson Eiver 



Fort Simpson 



do 



do 



Fort Randall 



Essex County, Ifew York 



do 



do 



.do. 

 .do. 

 .do. 

 -do. 



Saranac Lake, New York. 



do 



do « 



do 



do 



do 



Pennsylvania 



do 



do 



Tuscaloosa, Ala '.. 



Brookhaven, Miss 



3.02 

 2.82 

 2.83 

 2.75 

 2.73 

 2.75 

 2.68 

 2.64 

 2.63 

 2.68 

 2.55 

 2.45 

 2.32 

 2.30 

 2.86 

 2.70 

 2.90 

 2.55 

 2.90 

 2.60 

 2.60 

 2.40 

 2.40 

 2.40 

 2.32 

 2.30 

 2.47 

 2.40 

 2.35 

 2.20 

 2.40 

 2.17 

 2.50 

 2.50 

 2.47 

 2.80 

 2.60 



1.90 



1.64 



1.62 



1.61 



1.62 



1.57 



1.62 



1.55 



1.52 



1. 58 



1.50 



1.45 



1.40 



1.40 



1. 62' 



1.51 



1.78 



1.46 



1.61 



1.48 



1.38 



1.32 



1.38 



1.31 



1.32 



1.23 



1.37 



1.30 



1.31 



1.18 



1.48 



1.20 



1. 43 



1.48 



1.48 



1.61 



1.50 



Eemarks. 



Very old. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 

 Old. 



Do. 

 Old. P. " nigrescens'' A. & B. 



Do. 



Do. 

 Old. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



MUSTELA AMEEICANA. 



The fortj^-six male skulls of this species, of which measurements are 

 given below, are mainly from four or five localities differing widely in 

 latitude. A comparison of the average size of a considerable number 

 from each shows a well-marked decrease in size southward. Four skulls 

 from Peel River, the largest, and also from the most northerly locality, have 

 an average length of 3.39, and an average width of 2.07, the extremes 

 being 3.50 and 3.35 in length and 2.12 and 2.02 in width. Nine skulls from 

 the Yukon (probably mostly from near Fort Yukon) give an average length 

 of 3.34 and an averag^width of 1.98, the extremes being 3.55 and 3.00 

 in length and 2.15 and 1.73 in width. Five skulls from Fort Good Hope 

 give an average length of 3.24 and an average width of 1.95, the 

 extremes in leogth being 3.37 and 3.15 and in width 2.05 and 1.73. Ten 

 skulls from the northern shore of Lake Superior average 3.14 in length 

 and 1.76 in width, the extremes in length being 2.23 and 3.02 and in width. 

 1.89 and 165. Eight skulls from the vicinity of Umbagog Lake, Maine 

 (Coll. Mus. Comp. Zool.), average 2.96 in length and 1.72 in width, the 

 extremes in length, being 3.10 and 2.73, and in width 1.85 and 1.50. Five 

 skulls from Northeastern New York average 3.02 in length and 1.61 in 

 width, the extremes being in length 3.10 and 2.92 and in width 1.68 and 

 1.50. There is thus a gradual descent in the average length from 3.39 to 

 3.02. and in width from 2.07 to 1.61. The largest and the smallest of the 

 series are respectively 3.55 and 2.92 in length. Several fall as low as 

 3.00, and an equal number attain 3.50. The difference between the 



