MUSEUM OF COMPARATIVE ZOOLOGY. 17") 



dnskv, the black being almost obsolete, in which condition they seem not 

 essentially different from the figure and original description of P. hocamela 

 in the Fauna Italica. 



10. Putorius lutreolus Cuv. (P. vison Gappcr ; Vison lutreo- 

 cephala Gray ; Mustela lutreola Linn.) Mink. Common. 



I am not prepared to admit Audubon and Bachman's Little Black Mink 

 (P. nicjre<cens) as distinct from the above. Specimens referable to this 

 supposed species are not of uncommon occurrence. Mr. B. R. Ross con- 

 siders that the P. nigre.icens "is nothing more than the young of the P. 

 vison"* an opinion I have also long entertained. 



In this species we again have an animal of questioned identity, some 

 authors considering it the same as the European Mustela lutreola Linn., 

 while others maintain its distinctness. But the differences seem very 

 slight, and have generally been supposed to consist in the front of the upper 

 lip being white in the European, while there is no white on that of the 

 American ; in size, proportions, and general color, no one claims that they 

 materially differ. This single character is one of great variability in their 

 near allies, the ermines, some having the white margin of the upper lip 

 very broad, while in others it is very narrow and occasionally entirely 

 obsolete. The other white markings on the mink are notoriously variable, 

 some specimens having this color restricted to a very narrow chin patch, or 

 even entirely wanting, while in others there are spots of white on the throat 

 and between the fore legs ; in still others white spots occur also along the 

 middle of the abdomen and between the hind legs, forming an interrupted 

 median line of white patches. I also feel confident that I have seen 

 specimens of the American animal with a white margin to the upper lip. 

 Experienced trappers positively assure me that such examples are of 

 occasional occurrence.! Dr. Gray, however, gives a second character of 



* Natural History Review, July, 1862, p. 273 In a later paper in the Canadian Nat- 

 urali>t and Geologist (Vol. VI, p. 30), Mr. Ross says the P. nigrescens of Audubon and 

 Bach man are " merely common minks under three years of age." He states in another 

 place (1. c. p. 29), " I have remarked that the color of this animal, as well as that of the 

 otter and beaver, grows lighter as it advances in years, and that the white blotches 

 or spot- are of greater size and more distinct in the young than in the old. The color 

 of a young mink (under three years), when killed in season, is very handsome; its color 

 is often an almost pure black." I have myself observed a similar variation in color 

 with age in the common black rat, and in other mammals, as well as in many birds. 



I Since writing the above I find Mr. Ross says, in referring to Professor Baird's re- 

 mark that the American mink never has the edge of the upper lip white, " I have never 

 seen the whole of that part so colored, but iu one specimen now on my table there is a 

 white spot beneath the ncstril." 



