148 Proceedings of the Biological Society of Washington. 



appressed, leaving wide post-glenoid space with correspondingly large 

 open meatus [in dalli closer to glenoid process, pressing on and contract- 

 ing meatus tubes]; coronoid blade narrower above (more falcate). Canines 

 about the same; molars both upper and lower decidedly larger and more 

 massive and in details quite diflferent: M'^ exceptionally short and much 

 broader in middle than elsewhere, heel short and obliquely truncate on 

 outer side; M' large, much broader posteriorly than anteriorly; middle 

 lower molar peculiar, the twin cusps of entoconid very small, low, and 

 close together; metaconid exceptionally large and high, reducing the 

 posterior moiety of the crown to about one-third its length, instead of 

 about half as in dalli and most species. 



Young-adult female nuchek (No. 44049) /rom near Mt. St. Elias com- 

 pared with female dalli (No. 140085) /rom Copper River Delta: Skulls so 

 strikingly different as not to require close comparison, that of nuchek be- 

 ing light, slender, narrow, with low narrow flattened frontal region, long 

 slender rostrum, and light underjaw, while that of female dalli is massive, 

 broadly arched or domed, and with massive underjaw. The teeth also 

 differ strikingly. 



Yg. adult female nuchek CNo. iiOid) contrasted with old female cressonus 

 (No. 209881): Size slightly smaller (when fully adult probably same); 

 frontal shield much narrower and flatter, much less deeply sulcate, much 

 less swollen over orbits, and much shorter posteriorly; fronto-nasal region 

 in same plane (in $ cressonus strongly dished); sagittal crest longer; 

 nares smaller; canines (upper and lower) much longer; molars more 

 massive; W extremely short, much broadest in middle, with short 

 obliquely truncate heel (in cressonus normal). 



Female nuchek (No. 44049) compared with female kenaiensis (No. 

 133244) : Basal length essentially same; cranium narrower with narrower 

 braincase, narrower shield, and narrower rostrum ; zygomata less broadly 

 spreading ( would be more broadly spreading with age) ; occipito-sphenoid 

 shorter; palate essentially same length but narrower; postpalatal shelf 

 narrower; ramus more slender (conspicuously thinner below M2 and Ms) ; 

 its inferior border straighter, less upcurved posteriorly ; coronoid lower 

 and less narrowed above ; cusps of large premolars above and below much 

 more highly developed ; main cusp of upper premolars very much higher 

 relative to posterior cusp ; molar cusps also more strongly developed ; last 

 upper molar shorter and of pecuhar form as in the male. 



Skull measurements ( c? old, type).— Basal length 360 mm.;* occipito- 

 nasal length 358; palatal length 191; zygomatic breadth 248; interorbital 

 breadth 88. 



Ursus ophrust sp. nov. 



Type No. 210252 d* old, U. S. National Museum, Biological Survey 

 Collection. Type from eastern British Columbia (exact locality un- 

 known). Collected in 1915 by E. W. Darbey. 



Cranial characters.— Skull of adult male short, strongly dished, remark - 



* Estimated. 



t Ophrus with reference to the unusual brows. 



