A New Fossil Bear from <)kio. .">"> 



Ursus procerus sp. nov. 



Type No. 4214, United States National Museum. 



General characters. Skull about as long as that of the black bears (e. g., 

 Ursus americanus and -U. floridanus), but much more slender. Braincase 

 smaller and rostrum larger than in the black bears. Forehead deeply 

 concave. Canine teeth as in Ursus americanus, but molars fully as large 

 as those of Ursus arctos and the grizzly bears. 



Skull. Viewed from above, the skull of Ursus procerus differs from that 

 of U. americanus and U. floridanus principally in the position of the post- 

 orbital processes relatively to the total length of the skull. In the black 

 bears the distance from the tip of the nasals to a line joining the tips of 

 the postorbital processes is contained nearly or quite twice in that from 

 the latter point to inion. In U. procerus it is contained barely one and 

 one-half times. Postorbital processes short and blunt. Antinion broader 

 and longer than in U. americanus, strongly concave anteriorly, very little 

 elevated laterally and posteriorly. The horizontally expanded basal re 

 gion of the zygoma is about as broad as in U. americanus, but the shelv 

 ing portion of the squamosal behind the zygoma is much narrower and 

 more concave. The zygomatic arch as a whole stands out more widely 

 from the side of the skull than in U. americanus. In this respect it sug 

 gests the grizzly bears. 



Viewed from the side, the striking peculiarities of the skull become 

 fully apparent. The rostrum is so long, and its dorsal outline so nearly 

 parallel with the alveoli, that, combined with the general length and 

 shallowness of the braincase, it gives the skull a strongly canine aspect. 

 Distance from posterior border of infraorbital foramen to front of pre- 

 maxilla nearly one and one half times depth of rostrum through infra- 

 orbital foramen. In Ursm americanus and U. floridanus the same distance 

 scarcely exceeds the depth. The zygomatic arch as a whole does not 

 differ noticeably from that of U. americanus, though its anterior base ap 

 pears to be somewhat more lightly built. Braincase long and low. Oc 

 cipital condyle larger than in the black bears (fully as large as in U. hor- 

 rihilis) and standing out much more conspicuously behind the paroccipital 

 process. Sagittal crest and lambdoid crest well developed, but not un 

 usually large. Inion strongly overhanging. 



Viewed from beneath, the most striking peculiarities of the skull of 

 Ursus procerus are the length and breadth of the palate and the narrow 

 ness of the occipital region. The palate is nearly as long and fully as 

 broad as in the skull of a grizzly bear the basal length of which is 40 mm. 

 greater than that of U. procerus. The hinder part of the palate is so much 

 injured that its exact form cannot be determined ; but so far as the frag 

 ments may be taken as a guide the posterior palatal region did not differ 

 appreciably from the corresponding part of the black bear's skull. In- 

 terpterygoid fossa wider than in Ursus americanus. Distance from me 

 dian line of basioccipital to outer side of mastoid process 12 mm. less than 

 in the type skull of Ursus floridanus with approximably equal basal length. 

 Audital bullae smaller than in U. americanus and U. floridanus, but not 

 different in form. Glenoid fossa as in U. americanus. 



