170 U. 8. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



in the European P. erminea. Their projection beyond the vertebrae is about one-fifth of the 

 length of the caudal vertebras. 



The feet are large, the claws well developed. As usual there are ten naked balls on the fore 

 feet, and nine behind. The under surfaces of the feet are sparsely covered with hair, as is 

 generally the case with the weasels in summer. 



The predominating color of this species above is of a yellowish chestnut brown, considerably 

 lighter than in the P. noveboracensis, and much resembling the colors of P. frenata and 

 xanthogenys. From these, however, it is easily distinguished by the absence of light patches on 

 the cheeks and forehead. 



The under parts are of a pale brownish yellow ; nearly white about the chin and cheeks, and 

 more vividly yellow along the thighs. The line of separation between these colors is quite 

 indistinct ; indeed the bases of the hairs above, and the whole of the subjacent fur are yellowish, 

 like the belly, the chestnut tinge being imparted by the tips of the hairs. As far as can be 

 traced in this uncertainty of outline, the darker color extends on the outside of the arm only to 

 about the elbow ; the remainder of the fore leg being like the belly ; on the hind feet it extends 

 along the outside of the limbs to the toes, the upper surface of the feet being yellowish. The 

 upper surface of the tail is like the back ; beneath it is yellowish chestnut, darker than the 

 belly ; the tip for about two inches is lustrous black ; the color commencing not much posterior 

 to the end of the vertebras. 



The line separating the colors of the upper and under sides passes quite high up on the flanks; 

 the paler portion occupying fully two-fifths of the entire circumference around the middle of the 

 body. On the neck it occupies fully three-fifths of the circumference. The white of the cheeks 

 extends horizontally along the upper lip to the nostrils ; passing under the eye, at a distance 

 about half way between the eye and the mouth. 



As stated, this specimen is of very large size. When fresh, the head and body measured 12-j- 

 inches ; as a preserved skin, with no unusual amount of stretching, it is rather more than 15 

 inches ; the tail vertebrae now measure 5f inches ; with the hairs, 7 inches. These dimensions 

 are considerably larger than in the P. noveboracensis. The end of the skull is much broader 

 than in this spacies or in the ermine of Europe, although the teeth are of the same size (more 

 widely separated). The posterior upper molar is even narrower than in skulls of P. novebora- 

 ccnsis, of much smaller size. Its much lighter tints above, and the greater extent of the paler 

 color of the under parts, (over all the legs, beneath the base of the tail, upper lip, &c.,) with 

 the stiffer hairs, as well as its size, distinguish it from the other described American ermines. 

 The tail is much longer and with a shorter brush than in the European ermine. In some respects 

 it resembles the P. nigripes, Audubon and Bachman, but is smaller, has a longer tail, is without 

 the black of the head and feet, &c. 



The specimen described was taken on Milk river, upper Missouri, by Dr. Suckley, in August, 

 1853. Whether it turns white in winter is not known. 



