Preliminary Synopsis of American Bears. 79 



occupied by one or more accessory cusps. The posterior cusps of the talon 

 (hypoconid and entoconid) are nearly opposite in the Grizzlies and very 

 oblique in the Black bears. The Black bears agree further among them 

 selves and differ from the Grizzlies in the last lower premolar (pm 4 ), 

 which lacks the accessory cusps on the inner side, lacks the median sulcus 

 behind and the inner limiting ridge, and is uniformly much smaller; in 

 the last upper premolar (pm 4 ), which lacks all traces of the posterior ac 

 cessory cusp ; in the shape of the last upper molar (m 2 ), which is con 

 siderably broadest in the middle and is cut away posteriorly on the outer 

 side, with the heel shorter than in the Grizzlies. In Euarctos the coro- 

 noid process of the mandible rises at nearly a right angle from the hori 

 zontal ramus ; in Ursus proper by a gradual slope. 



Ursus americanus Pallas. Black Bear. 

 Ursus americanus Pallas, Spicilegia Zoologica, fasc. XIV, pp. 5-7, 1780. 



Type locality. Eastern North America. 



1 Geographic distribution. Forest-covered parts of North America north 

 of the Lower Austral zone. 



Characters. Size small ; frontal region usually moderately elevated ; 

 zygomata spreading; molar teeth small. 



The characters of the subgenus suffice to distinguish Ursus americanus 

 from all other American bears except luteolus and floridanus. From these 

 it differs in the shortness of the skull as a whole, in the smaller size of 

 the molar teeth, and in other particulars pointed out under the latter 

 species. 



Measurements of skulls. Average of 4 adult males from New York State : 

 Basilar length of Hensel, 254; postpalatal length, 118; basion to plane of 

 front m 2 , 168; zygomatic breadth, 184; ratio of zygomatic breadth to 

 basilar length, 75. 



Ursus luteolus Griffith. Louisiana Bear. 



Ursus luteolus Griffith, Carnivorous Animals, pp. 236-237 (with col. pi.), 

 1821. 

 Merriam: Proc. Biol. Soc. Wash., VIII, pp. 147-152, Dec. 29, 1893. 



Type locality. Louisiana. 



Geographic distribution. Louisiana and Texas and probably other parts 

 of Austroriparian Zone. 



Characters. Size large ; skull long and flat; fron to-parietal region de 

 pressed ; profile of top of skull (including crest) nearly a straight line ; 

 sagittal crest long and high, about half the length of upper side of skull 

 in old age. Contrasted with old skulls of male Black bears from the 

 Adirondacks, in northern New York, the three old male skulls from Mer 

 Rouge, Louisiana, differ uniformly in the following particulars : They are 

 longer and flatter ; the occipito-sphenoid length is greater ; the distance 

 from foramen magnum to plane of front of last upper molar is greater; 

 the ratio of zygomatic breadth to basilar length is less (average, 64.6 in 

 stead of 75 percent) ; the ratio of postpalatal length to occipito-sphenoid 

 length is considerably greater. 



