222 U. S. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



size, the usual absence of most of the small premolars, and the grayish white color of the tips 

 of the hairs on the body, the American grizzly forms a remarkable and extreme geographical 

 variety of the Old World, Ursus arctos; very closely related to the bear of the west coast of 

 Behring's Straits, and through this and others, by insensible degrees, affiliating with the common 

 well known brov\n bear. 



In the lack of sufficient materials for comparing the grizzly with the Old World bear, I cannot 

 gainsay thece conclusions, although perhaps the description of skins and skulls of the American 

 animal herein presented may throw more light on the subject. 1 



Skull. The skull of a grizzly bear from California, of middle age, (2037,) obtained at San 

 Francisco, exhibits the teeth almost perfectly unworn, excepting the extreme points of the 

 inner tubercles of the upper molars, and the outer of the lower. The sagittal crest extends 

 further forward than in the smaller American bears of the same age, reaching to the coronal 

 suture. 



The upper outline of the skull is nearly straight from the occiput to the middle of the pari 

 etal crest. It then curves gently upwards, attaining its greatest elevation over the beginning 

 of the posterior fourth of the frontal ; from this it slopes downwards in a nearly straight or very 

 gently convex line to the anterior third of the nasal, and passes off more nearly horizontally and 

 straight. The curve is much less convex than in the U. americanus, and the greatest convexity 

 of the arc of curvature, and greatest height above its chord, is in the posterior fourth instead of 

 in the centre. The forehead is plane between the orbital processes in its central third, exterior 

 and posterior to this it is very gently convex, much less so than in the U. americanus. There 

 is a decided angular depression along the middle of the nasal bones, except in the posterior 

 fourth, where it is much less. 



The greater elongation of the skull in the grizzly bear is shown in the proportion which the 

 width between the zygomata bears to the total length of orthographic proportion, being as 507 

 to 1,000, or nearly as one to two. 



The zygomatic arch of this species is very little curved in either direction, being nearly 

 straight, viewed from above, and only moderately arched. The coronoid process of the lower 

 jaw is moderately concave on its posterior outline and forms a well defined right-angle with the 

 superior, which curves very little downwards to meet it. 



A rather older specimen from the upper Missouri, lent for examination by Dr. Stevens of St. 

 Louis, exhibits much the same characters, although rather shorter absolutely, and broader in 

 proportion to its length. In this and a very old specimen from Monterey, (1218,) the median 

 sagittal crest has not advanced beyond the coronal suture, although the temporal ridges are 

 very decided and rise above the level of the forehead. In neither of these is there any great 

 difference in the upper profile of the head, except that in No. 1218 the forehead is more depressed, 

 so as to cause a slight concavity from the middle of the frontal bone to the end of the nasals. 

 The forehead between the post orbital processes is also concave transversely, the orbital process 

 only being rounded off exteriorly. The skull has become much broader in proportion to the 

 length. (616.) 



1 As this article is passing through the press, I have received an elaborate paper, entitled " Ueber die Selbststandigkeit 

 der Species dcs Ursus ftrox, Desm., von Prinz Max von Wied, mil anatomischen Bemerkungen von Dr. C. Mayer," an extract 

 from the Verhandlungen der Kais. Lcop. Carol. Akad. der Naturforscher, vol. XXVI. The date is not given, but it is either 

 1856 or 1857. The species is very elaborately discussed, both as to its external form and internal structure. The authors come 

 lo the conclusion, after reviewing all of MiddendorfF's arguments, that the species is essentially distinct, as a species, from the 

 European Ursus arctos, especially in the shorter ears and longer claws, as well as in certain osteological peculiarities. 



