MAMMALS* 



27 



posterior molar above. The posterior root of the zygomatic arch, viewed from ahove, is narrower 

 and more emarginated hehind and before- The base of the head is much more arched longitu- 

 dinally, in this respect approaching the Polar bear It has been already stated that a straight 

 line tangent to the occiput and intermaxillary passes three-quarters of an inch from the bottom 

 of the palate, instead of less than half an inch, as in the California bears. 



As the result of the above comparisons, I have come to the conclusion that the grizzly bear 



of the southern Rocky mountains differs appreciably from the grizzly of the Pacific coast in 

 smaller size, smaller teeth, rather broader head, and the other features adduced above, so that 

 there is no difficulty in distinguishing them. Whether this is indicative of a different species 



or merely of a local race, I cannot say; an examination of corresponding specimens from the 

 Upper Missouri, which I hope hereafter to make, will throw much liglit on the subject. 



I have had no means of comparing the adult skulls of this bear with those of U, arclos of 

 Europe. The latter species, however, as shown by a two year old skull, 1033, from Sweden, is 

 considerably broader. The teeth are of much the same size, those of ardos rather larger. The 

 last upper molar in the European bear has the posterior half more free from tubercles and more 

 twisted, and the wrinkles on the crowns are finer and more numerous. The third molar from 

 behind is much narrower in U, arctos, in this respect even exceeding the California grizzly; the 



inner lobe is single and much reduced in size. The posterior lower molars are of smaller shape 

 and proportion. 



* 



This bear exceeds the ITrsiis americanus and cinnamoneus very much in size^ and has other 

 differences, which are readily appreciable. The arch of the head does not extend in a uniform 

 convex curve, as in these species, and the forehead is plane and even concave ; the anterior 

 portion of the dorsal outline is usually convex in the small species. The proportional width of 

 the head is less in the present species ; the muzzle is longer. The zygomatic arch is more 

 massive, especially the posterior portion, which is as high or higher than the anterior, instead of 

 being considerably less. There is a much greater concavity of the posterior half of the palate 

 than in Ursus americanus, where this is quite convex^ and with various ridges not seen in the 

 present species. Tlie notch of the palate is distant from the posterior upper molar by the 

 length of the latter tooth, while this distance is considerably greater in the smaller bears. 



The most appreciable differences, however, next to the shape of the zygoma, size and proportion 

 of the head, &c., are found in the teeth. These are proportionably very much larger than in 

 U. cinnamoneus y and appreciably exceed those of 77. americanus. The tliird upper molar from 

 behind is, in particular, larger, broader, and with two or three lobes on the inner half, instead 

 of a single and much smaller one. The crowns of the molars generally are more tuberculated, 

 and less finely wrinkled than in U. americanus. 



