338 



Measurements of the molar teeth of UKSUS ARCTOS tt var. 



UBSUS AMERICANUS. 



Seventeen skulls of this species, embracing all the aged ones in the 

 collection, seem to indicate a slight increase in size to the southward. 

 Four aged skulls from Louisiana and Florida range in length from 12.50 

 to 13.10, and three others, more or less immature, would doubtless have 

 attained an equal size had they lived to be as old. A Georgia specimen, 

 also not full-grown, has a length of 11.15, and in old age would probably 

 have considerably exceeded 12.00. The other specimens, all full-grown 

 and some of them very old, range from 9.90 to 12.15, most of them fall- 

 ing between 10.25 and 11.75. The largest (12.15) is from Puget Sound. 

 A New York specimen comes next in size (11.90); New Mexican speci- 

 mens next, the Alaskan being the smallest. This certainly points to a 

 southward increase in size ; but a much larger series would, of course, 

 be necessary in order to establish positively whether the increase is in 

 this direction. It would seem natural to expect it to be so, since the 

 Bear is a hibernating animal, and is active for a much shorter period 

 in northern than in southern localities. 



It seems worthy of remark that only a small proportion of the skulls 

 of Bears, and even of other Carnivora, including the Minks, Otters, and 

 Martens, seen in collections, are specimens of mature age. The propor- 

 tion of fully adult and very aged specimens is much greater among those 

 from the unsettled parts of the continent than among those from the 

 older States, owing, doubtless, to these animals being so closely hunted 

 in the more settled districts that they rarely live to a very great age. 



