86 NORTH AMERICAN MUSTELID.E. 



hind legs. This distiuctiou is confirmed, as an average char- 

 acter, by the specimens before me, though, like other matters 

 of mere degree, it is subject to some uncertainty of determina- 

 tion. I similarly endorse, on the whole, a lighter, grayer, more 

 uniform coloration of J/, martes, although in the interminable 

 variations of ^1/. ainericana probably no infallible distinctions 

 can be substantiated. But all these points have a certain value 

 wheu correlated, as they should be, with the cranial and dental 

 i:>eculiarities. These are decided, and, I think, not open to 

 reasonable question as affording good specific characters. 

 Baird has tabulated most of them, and the specimens I have 

 examined confirm nearly all the distinctions he has sought to 

 establish. While he has uot, as asserted by Gray, overlooked 

 certain dental peculiarities, he has perhaps not laid the stress 

 upon them which is warranted. Gray rests secure, I think, iu 

 basing the primary distinction upon the remarkable features 

 presented by the back upper molar. We may bring the points 

 to mind by saying that in M. martes we find an hourglass- 

 shaped tooth with one bulb (the inner) very much larger than 

 the other; while iu M. americana there is less median constric- 

 tion, nearly an equality iu size of the two bulbs, and an emar- 

 ginate instead of simply convex exterior contour of the outer 

 bulb. There are coordinated dental characters : the last upper 

 premolar in M. martes has a strong, directly transverse, inner 

 fang; the same in M. americana is smaller and oblique. The 

 penultimate lower molar iu M. martes develops a compara- 

 tively strong supplementary cusp at the base on the inner side 

 of the main cusp, represented in M. americana merely by a 

 slight heel. It is to these dental characters that I primarily 

 refer in predicating, as I do, specific validity of M. americana. 

 I coordinate them with the cranial characters elsewhere de- 

 tailed, and supplement them with the less essential external 

 features already noted, in coming to the conclusion that the 

 American is not the Pine Marten of Europe. 



The question then narrows to the characters of .1/. americana 

 iu comparison Avith those of M. ziheUina, the true "Eussian^ 

 Sable. Gray separates the two upon dental peculiarities; the 

 Sable having, according to his determination, the same dental 

 characters as M. martes. I regret that I have not been able to 

 verify this. If it indeed holds, it would be sufficient to settle 

 the issue between 21. ziheUina and M. americana., whatever 

 might then become of the ascribed and supposed differences 



