Prelhiiinari/ Sijnopsis of American Bears. G9 



Key to the Big Bears op America. 



Molars small and weak ; pin * with inner cusp obso- 

 lete or small ; m - without decided heel genus Thalarctos. 



Color, white Thalarctos marUbnus. 



INIolars large and powerful ; pm * with inner cusp 



strongly developed ; m ' with enormous heel genus Ursus. 



Size huge. 



Size largest (skull reaching 440 mm. in greatest 

 length); frontal region enormous!}' elevated 



above and behind orbits Ursus mlddendorffi. 



Size somewhat smaller (skull less than 425 in great- 

 est length) ; frontal region nearly flat. 



pm * very large and quadrituberculate ; pm ^ 

 large and high without heel ; m j without 



clear interspace on inner side Ursus dalli. 



pm * normal ; pm 4 moderate, normally with 

 cusp on cinguhim in front of main cusp ; 

 m 1 with clear intersiiace on inner side .... Ur.v(s siikensis. 



Size medium or relatively small. 



Temporal impressions turning in abruptly from 

 postorbital jirocesses, nearly at right angle to 



cranial axis ; skull short Ursus richardsoni. 



Temporal impressions not turning in abruptly 

 from postorbital processes; skull longer. 

 Frontal elevated and usually convex between 



postorbital processes Ursus hurribilis. 



Frontal flattened and concave between post- 



orliital processes Ursus horrissus. 



Ursus mlddendorffi sp. nov. Kadiak Bear. 

 PI. IV, figs. 2, 3 ; pi. V, fig. 2 ; pi. VI, fig. 2. 



Type from Kadiak Island, Alaska, No. 54793, S" ad., U. S. Nat. Mus., 

 Dept. Agric. coll. Collected July 3, 1893, by B. J. Bretherton. (Original 

 No. 176.) 



Cfmracters. — Size huge; largest of living bears, though only slightly 

 larger than Ursus beringiana MiddendorfF, from Kamschatka ; frontal re- 

 gion in male enormously elevated, highly arched, and relatively narrow ; 

 zygomata bowed outward to an extraordinary degree; postzygomatic 

 part of skull very short. 



The bear of Kadiak Island needs comparison with only a single spe- 

 cies — Ursus beringiana, of Kamschatka. It requires no comparison 

 with the American Grizzlies ( I'rsus liorribiUs Ord) or with the Barren 

 Ground bear ( Ursus richardsoni Mayne Reid). Contrasted with the Kam- 

 schatka bear the forehead of the male is very much higher, more swollen 

 above and l)ehind the postorbital processes, narrower, and more rounded ; 



