OCR Text |
Show 340 than the middle third, though sometimes equaling it; but it is never wider, as it almost invariably is in U. horribilis and V. arctos. The Paget Sound specimens have the anterior third the narrowest; in Alaskan specimens, it reaches its extreme width, while New York and Louisiana examples present the medium phase. The skulls of TJ. cinnamomem do not seem to be in any way distinguishable from average skulls of TJ. americanus, the distinction between them being one of color only and inconstant as characterizing any particular locality or region. The upper molar teeth of TJ. americanus, as shown by the subjoined measurements, differ considerably in size in fully adult specimens. The first molars range in length of cro. wn from 0.40 to 0.52, and in the width of the same from 0.27 to 0.42. The second ranges in length from 0.67 to 0.78; the third from 0.94 to 1.22, and in width from 0.51 to 0.67! In two specimens, with the first 0.44 in length, the third in one has a length of only 0.94 and the other 1.07! In another, the length of the first molar is 0.41 and the third 1.11. In still another, with the length of the first molar 0.43, the length of the third is 0.96. In two others, while the length of the first molar is 0.50 in each, the third molar in one has a length of 1.22 and in the other 1.15. The largest skulls of TJ. americanus nearly equal in size the smaller skulls of TJ. arctos horribilis, and actually overlap the series from Franklin Bay and the measurements given by authors of the true arctos of the Old World. In view of this fact, and of the great range of individual variation in size, cranial and dental characters, and the unreliability of color as a specific character, I too hastily, in former papers,* referred all the American land- bears, including the U. americanus, to the U. aretosi which I am now convinced was a mistake; TJ. americanus being, I now believe, unquestionably specifically distinct, and the Grizzly subspecifi-cally separable from the TJ. arctos of the Old World. * Bulletin Mus. Comp. Zool., vol. i, pp. 184- 192, Oct.. 1869: Bulletin Essex Institute, vol. vi, pp. 40,54,59,63,1874. |