DESCRIPTION OF PUTbRIUS LONGICAUDA. 137 



cliin. Black on end of tail almost reduced to the terminal pencil alone, 

 scarcely i the whole length. Color entirely white in winter. Male, total 

 length of head and body, 10.50 ; tail-vertebrje 6.75 ; tail with hairs 8.50. Fe- 

 male, total length of head and body, 8.50; tail vertebrae, 5.75; tail with 

 hairs, 6.75. 



Description. * 



The size is eatirely within the range of that of P. erminea, 

 and there is little to note in this respect, excepting the greater 

 length of the tail ; the general build, however, appears stouter 

 than is usual in P. erminea, the muzzle blunter. The tail is 

 remarkably long — not that it is entirely beyond the maximum of 

 that of erminea, but that when shortest it is about at such 

 maximum, and that its normal average is beyond the average 

 of that of P. erminea. The two animals being of substantially 

 the same size of body, the tail is relatively longer — including 

 the hairs it is three-fourths to four-fifths the length of the body 

 and head. The black on the tail is normally restricted to the 

 minimum — or even beyond this — of ordinary erminea; it occu- 

 pies scarcely anything more than the terminal pencil alone, 

 extending le^s than half an inch on the vertebrae. The upper 

 parts are much as in erminea, but there is a peculiar olivaceous 

 cast, owing to admixture of some green in the brown — not that 

 any green shows as such, but it gives a particular tone to the 

 parts. Below, and on both sets of paws, the color is a rich and 

 beautiful buffy-yellow mixed with salmon color, quite different 

 from the clear sulphury of P. erminea. This color is abruptly 

 displayed against the pure white of the chin and cheeks. The 

 female is considerably smaller than the male, as usual in this 

 genus, but is not otherwise different. (This particular specimen 

 is much lighter than her mate, but such distinction will not 

 hold.) The following measurements were carefully taken in the 

 flesh :— 



* From a pair in the Coues collection, killed in August, 1874, in North- 

 western Montana. 



