152 Proceedings of the Biological Society of Washington. 



nasal length 353; palatal length 183; zygomatic breadth 245; interorbital 

 breadth 91.5. 



Ursus washake sp. nov. 



Type No. 213005 6^ adult (rather old), U. S. National Museum, Bio- 

 logical Survey Collection. From North Fork Shoshone River, Absaroka 

 Mts., western Wyoming (between Bighorn Basin and Yellowstone Na- 

 tional Park). Killed September, 1913, by Col. J. A. McGuire. 



Cranial characters. — Old male (the type): Size medium, about equal- 

 ing male shoshone and male horriaeus ; skull rather short and high, 

 moderately arched, with broad, elevated postorbitals and rather broadly 

 outbowed zygomata. Frontal shield rather narrow', sloping strongly up- 

 ward anteriorly, highest at postorbital processes; horizontal posteriorly, 

 broadly concave between postorbital processes; postorbital processes 

 large, broad, subtriangular as viewed from above, outstanding, elevated 

 and slightly arched, rising well above frontal plane and passing anteriorly 

 into thickened orbital rims; fronto-nasal region dished (change of angle 

 about middle of nasals); rostrum rather small, strongly compressed hori- 

 zontally between nasals and roots of canines, making nasals appear ele- 

 vated ; anterior nares small ; zygomata rather slender, broadly spreading, 

 rounded and strongly outbowed posteriorly, only slightly expanded ver- 

 tically ; sagittal crest low ; postpalatal shelf broad, flat, and rather short; 

 occipito-sphenoid 87 mm. (^distance from front of canine to or slightly 

 beyond middle of M^). Lower jaw moderate; ramus bellied posteriorly; 

 coronoid blade high and rather falcate, the apex cutting plane of condyle 

 (line from apex to tip of angular process passing well behind condyle). 

 Teeth moderate or rather large ; M^ large. 



Cranial comparisons. — Old male washake (type) compared with adult 

 male shoshone of same region : Size essentially same, but general appear- 

 ance of skull very diflerent ; braincase broadly and rather flatly depressed 

 anteriorly instead of narrowing to keeled crest ; frontal shield more 

 abruptly uplifted anteriorly, highest at postorbital processes [in shoshone 

 rising gradually and highest midway between postorbitals and parietals] ; 

 postorbital processes large, massive, subtriangular, elevated and somewhat 

 arched [in shoshone slender, peglike, and somewhat depressed]; rostrum 

 more compressed horizontally below nasals ; zygomata much more broadly 

 outstanding; postpalatal shelf broader; angular process of lower jaw longer 

 and more produced. 



Compared with adult male ophrus from eastern British Columbia (the 

 type) : Size about the same but appearing smaller; frontal shield less ele- 

 vated and less deeply concave ; fronto-nasal region elevated instead of 

 sulcate-dished ; zygomata less widely outbowed; postorbitals much broader 

 and less elevated; orbital rims less swollen; postpalatal shelf shorter and 

 broader ; mastoids shorter ; nares smaller and lower. Lower jaw more 

 massive ; inferior border of ramus more swollen and much more bellied 

 posteriorly; coronoid blade higher and more falcate, the apex reaching 

 much farther posteriorly (cutting plane of hinder part of condyle). 



