Canis nubilus. Say.

To distinguish between the numerous races of Wolves which are scattered¹ more or less abundantly over nearly the entire surface of the earth; to determine that such and such variations are the result of original formation, and that such and such others are merely the product of accidental circumstances; in other words, to establish clear and tangible² grounds of specific distinction between animals so varied³ in external appearance, but corresponding so perfectly⁴ in every essential particular, while the shades of character by which they differ, although in many cases strikingly marked, are for the most part so unimportant, or so little permanent, as scarcely to be[94] deserving of notice,—is unquestionably one of the most difficult problems, to the solution of which the zoologist⁵ has to apply himself.

In internal and anatomical structure, on which modern naturalists⁶ are agreed that the greatest reliance ought to be placed in the distinction of closely approximating species, there is in the various races of Wolves no deviation⁷ from the common type of sufficient importance to warrant their separation from each other; neither does their outward form, excepting only in size and in the comparative measurement of parts, differ in any remarkable⁸ degree. In colour it is true that the most striking variations are observable, their hair exhibiting almost every intermediate shade between the opposite extremes of black and white. But it must be obvious that on this character, taken by itself, it would be absurd to insist as a ground of specific distinction, when we reflect on the influence which climate and other external accidents must necessarily exercise on animals so extensively dispersed

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