FIELD BOOK OF MAMMALS 



difficult task for a museum, with a fair-sized collection of 

 these animals, to identify specimens. In the attempt to make 

 this field book complete, a synopsis, more or less brief, was 

 written for each and every one of the 84 forms, but in the 

 final analysis it was discarded in favor of a much briefer, more 

 comprehensive treatment which is open to criticism, it is 

 admitted, but which is far less confusing to the lay reader. 

 "The differences formerly supposed to exist between the 

 Grizzlies and the Big Brown Bears appear, in the light of the 

 material now available, to distinguish certain groups of species 

 from certain other groups, rather than the Grizzlies col- 

 lectively from the Big Brown Bears collectively. In other 

 words, the differences between the Grizzlies on the one hand 

 and the Big Brown Bears on the other are neither so great nor 

 so constant as at one time believed. And there are species 

 which in the present state of knowledge can not be positively 

 referred to either group. In fact, it seems at least possible 

 that certain species which appear to belong with the Grizzlies 

 are closely related to certain other species which clearly belong 

 with the Big Brown Bears. The typical Brown Bears differ 

 from the typical Grizzlies in peculiarities of color, claws, skull, 

 and teeth. The color of the former is more uniform, with less 

 of the surface grizzling due to admixture of pale-tipped hairs; 

 the claws are shorter, more curved, darker, and scurfy instead 

 of smooth; the skull is more massive; the fourth lower premolar 

 is conical, lacking the sulcate heel of the true Grizzlies. But 

 these are average differences, not one of which holds true 

 throughout the group. Most of the specimens in museums 

 consist of skulls only, unaccompanied by skins or claws, 

 leaving a doubt as to the external characters; and in old bears 

 the important fourth lower premolar is likely to be so worn 

 that its original form can not be made out. And, worst of all, 

 some of the Grizzlies lack the distinctive type of premolar, 

 leaving only the skull as a guide to their affinities. ' ' (Merriam, 

 North American Fauna, No, 41, p. 12, 1918.) 



Big Plains Grizzly; Silvertip. — Ursns horrihilis horrihilis Ord. 



The animal described above. Found on the Great Plains 



bordering the Missouri River in eastern Montana and 



the Dakotas; limits of range unknown. 

 Baird Grizzly. — Ursus horrihilis bairdi (Merriam). 



"Probably a mountain animal, while its neighbor horrihilis 



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