MAMMALS—MARTINAE—PUTORIUS RICHARDSONII. 165 
and on the posterior portion of the back. The tail is full and rather bushy, the vertebrae measur- 
ing 3.90 inches; with the hairs, 5.60. The black tip is very well defined, and occupies nearly 
one half the total length of the tail. The end of the vertebre extends a little beyond 
the first third of this black portion. In the character of the tail, it resembles the European 
ermine more than P. noveboracensis does; its tail is, however, more slender and longer; the 
black less extended in proportion to the white. It is, however, quite possible that this specimen 
may belong to P. cicognanii, (see this species ;) and that the latter species, in higher latitudes, 
attains a greater size than it does in Massachusetts. 
The species is readily distinguished from Putorius cicognanii by the longer tail, the vertebrae 
alone of which are half the length of the body, instead of requiring the entire tail to effect the 
same proportion. It is much smaller and darker than P. noveboracensis, and the whole upper _ 
lip is brown. 
The Mustela agilis, of Tschudi, Fauna Peruana, 1844-46, p. 110, (not of Audubon & Bachman,) _ 
is very slender in form, with a small and pointed head ; the tail much shorter than the body. 
The head, back, and tail are reddish gray; the latter a little darkest at the tip. The under 
parts generally are grayish white. The base of the hairs above is gray ; then follows a broad 
grayish yellow ring, succeeded by a reddish brown tip. The head above is either entirely dark 
brown or with a white border to the upper lip. The length of body to root of tail, 9.10 inches; 
the tail, 4.44 inches ; the head 1,5 inches. 
This species, a true Putorius, differs materially from the larger North American weasels, in 
the absence of a black tip to the short tail; in this respect resembling the Putorius cicognanii. 
It probably bears a near resemblance to Putorius boccamela, of Italy. The lack of white or 
yellow blotches on the forehead distinguishes it from either P. frenata or xanthogenys. It 
inhabits the barren, cold plateaus of the Peruvian Cordilleras, and is the only true weasel well 
established as inhabiting South America. 
The measurements and other indications of Richardson, as well as the comparison with a 
larger variety, together with the known facts of the more Arctic distribution of the smaller long 
tailed ermine, leave no doubt on my mind that the common ermine, as described by Richardson, 
is really the Putorius agilis of Audubon & Bachman. The name of Bonaparte has priority over 
the last mentioned one, which would at any rate be untenable, as it had been applied previously 
by Tschudi to a Peruvian species, as already mentioned. 
The geographical distribution of this small ermine, as shown by the accompanying list of 
localities, is very extensive, and it appears to range much further to the north than the large 
species. Richardson describes a specimen obtained at Fort Franklin, Great Bear Lake, latitude 
65° 11'56” N. The Smithsonian collection embraces specimens from Halifax to Vancouver’s 
Island, and as far south as Massachusetts. Its extreme southern range in the Atlantic States is 
not yet ascertained, though it is probably replaced there by the P. noveboracensis. 
Some objection may be made to the identification of this species with that described by 
Richardson, on the ground that he gives the length at eleven inches. A skin of nine inches 
might very readily be stretched to that length, and the fact is proved by the measurements of 
the tail, which are, vertebre four inches, and with hairs five. The largest American ermine 
weasels I have ever seen, before being skinned, measured less than eleven inches, even when the 
tail vertebree were five or six inches long. 
