PLEISTOCENE VERTEBRATES FROM CUMBERLAND CAVE 25 



The skull of E. vitabilis is not so robust as that of Ursv^ horribilis, 

 nor is the muzzle so elongate. In the relative proportions of the skull 

 and lower jaw the Cumberland Cave form compares favorably with 

 living black bears of North America. The shape as well as the size 

 of the fossil skulls varies somewhat, but no important or consistent 

 differences can be cited to establish a division within the fossil collec- 

 tion, or to distinguish them from Recent forms on the osseous parts 

 alone. 



In the dentition E. vitabilis shows points of resemblance to both 

 E. americanus and E. luteolus, but in some characters it seems clearly 

 distinguished from them. E. luteolus possesses teeth averaging some- 

 what greater size than does E. americanus. Also, in E. luteolus the 

 cheek teeth appear relatively wider and P* is better developed. The 

 upper and lower teeth of E. vitabilis are relatively much narrower 

 than in E. luteolus and average somewhat narrower than comparable 

 teeth in E. americanus. Upper and lower canines in the fossil form 

 are usually large as in E. luteolus. 



P* in E. vitabilis is noticeably well developed, with a prominent 

 internal cusp placed opposite the notch between paracone and meta- 

 cone. This tooth is much larger than in E. americanus, and in several 

 fossil specimens it is appreciably larger than in E. luteolus. The 

 corresponding tooth in U. horribilis is in turn very much larger than 

 in E. intabilis, and in the grizzly the protocone is accompanied by 

 several accessory cuspules. 



M\ other than being relatively somewhat narrower, differs little 

 from this tooth in E. americanus. M^ is an elongate tooth that does 

 not usually taper so abruptly posterior to the metacone as is common 

 in E. americanus; however, this tooth does not reach the development 

 and proportions seen in U. horribilis. 



The anterior lower premolars are more commonly present m 

 E. mtabilis than in E. americanus and E. luteolus and are usually better 

 developed. P* averages larger than in the living black bears, but it 

 is not nearly so large as in U. horribilis, nor does it show the sulcate 

 heel, which characterizes this tooth in the grizzly. 



M^ is a narrow tooth ha\4ng a trigonid cuspate as in the ursids not 

 trenchant as in the tremarctine forms. The succeeding molars are 

 also narrow but otherwise resemble corresponding teeth in Recent 

 black bears. 



A large amount of limb and foot material of Euarctos mtabilis is 

 included in the collection. The various elements for the most part 

 were unassociated. A noticeable variation in size is seen and no 

 consistent differences were observed which would serve to distinguish 

 the fossil from the li\'ing bear. 



The skull of E. mtabilis differs from that of Ursus procerus Miller 

 (1899) from the Pleistocene of Oliio in haAang a less concave dorsal 



