134 Proceedings of the Biological Society of Washington. 



ence is, not that the Admiralty Grizzly is derived from the 

 Chichagof Island species, but that the Chichagof Island form is 

 a descendant of the ancestor of the one from Admiralty Island. 



The varying degrees of divergence of the island forms furnish 

 an interesting index to the relative time when each obtained a 

 foothold on the island. In this connection it is well to bear in 

 mind that the breadth of the strait separating Admiralty Island 

 from the mainland is at its narrowest point not more than five 

 miles. 



The mainland Big Bears with their representatives on Ad- 

 miralty Island here provisionally recognized are: 



Mainland species Admiralty Island species 



Ursus dalli Ursus shirasi 



stikeenensis mirabilis 



orgilos insularis 



kwakivtl neglectus 



caurinus eulophus 



Descriptions of the heretofore undescribed bears follow : 



Ursus apache sp. nov. 



Type No. 212436 d* adult, U. S. National Museum, Biological Survey 

 Collection. Killed on Whorton Creek on south slope of White Mts., 

 eastern Arizona (a few miles west of Blue), April 3, 1913, by B. V. Lilly. 



Cranial characters. — Skull of adult male (the type): Short, broad, 

 and low, rather massive, moderately dished, with broad frontal shield 

 and exceedingly broad outstanding postorbitals. Frontal shield broad, 

 shallowly sulcate medially between orbits; very slightly and rather flatly 

 swollen over orbits; long-pointed posteriorly, meeting short sagittal crest 

 at fronto-parietal suture; rostrum short, high, and rather narrow; zygo- 

 mata strongly outbowed and outstanding anteriorly as well as posteriorly; 

 ramus of jaw rather short, bellied under last molars; coronoid blade high, 

 sloping strongly outward, the apex overarching shallow coronoid notch, 

 but not cutting plane of condyle ; dentition moderate. 



Cranial comparisons. — Old male apache compared laith male adult 

 absarokus, apparently its nearest relative, the skull of apache differs 

 as follows : vault of cranium lower, less arched ; frontal shield broader 

 and flatter; postorbitals much broader and flatter, standing out more 

 horizontally ; naso-frontal region more depressed ; rostrum shorter ; orbits 

 notably smaller (lower vertically) ; squamosal trough shorter anteropos- 

 teriorly ; zygomata very much more strongly outbowed and conspicuously 

 more outstanding anteriorly; lower jaw and inferior border of ramus 

 shorter; coronoid blade of equal height; teeth slightly smaller (differ- 

 ence slight). 



