54 MAMMALIA. 



tection of the species. And this leads us to the consideration of 

 of an important element in the discussion, to wit, the cause, or causes, 

 which, acting through a long period of years, resulted in establishing 

 this seasonal changre in color. If the Ermine is the direct descendant 

 of a dark-colored animal, and was, originally, an inhabitant of the tem- 

 perate zone, it would have found, upon extending its range northward, 

 and indeed, wherever snow covers the ground in winter, that its dark 

 color, by rendering it conspicuous on the white: surface, proved a dis- 

 advantage to it, both in the pursuit of its prey, and in the escape from 

 its natural enemies. Therefore, by individual variation, and by the 

 effect of light upon the snow, aided and directed by the laws of nat- 

 ural selection, it finally got to assume, during the winter season, a 

 dress that is in harmony with the objects among which it moves — a 

 garb well adapted for the maintenance and preservation of the species. 

 Mr. Bell's theory, that the object of the white color is, by retard- 

 ing radiation, to increase the amount of heat retained by the animal, 

 is not only inadequate to account for the facts in the case, but, it 

 seems to me, arises from straining a point (and an imagination as 

 well ! ) to invent an improbable hypothesis for the explanation of a 

 phenomenon the rationale of which is almost self-evieient. The 

 cause cited must have played the part of a very subordinate factor. 



PUTORIUS VISON (Brisson) Gapper. 



Mink. 



The Mink is a well-known and tolerably abundant inhabitant of 

 this region, frequenting water-courses, and preying upon muskrats, 

 rats, mice, birds and their eggs, fish, frogs, turtle's eggs, cray-fish, 

 and fresh-water mussels. It occasionally enters the poultry-yard of 

 the border farmer and thins out his stock of ducks and chickens. It 

 also feeds upon the rabbit; and on the salt-water marshes of the South 

 kills great numbers of the clapper rail and the sharp -tailed and sea- 

 side finches. 



