336 MUSTELA. 



broader and shorter; audital bullae shorter and less inflated, frontals 

 broader; shelf of palate less produced behind plane of last molar; first 

 upper premolar smaller and more crowded; upper molars larger; 

 upper sectorial larger, with inner lobe larger and longer, projecting 

 anteriorly beyond the plane of the anterior lobe; lower sectorial has 

 inner cusp wanting. All these as compared with M. americana. 

 Other minute variations in size of remaining teeth also exist. 



Color. Like J/, americana, the chief difference being that the 

 irregular markings of the throat and under surface generally are 

 orange red instead of whitish or 3-ellowish. 



Afeasuremenis. Skull: basilar length, 78; Hensel, 70.7; zygo- 

 matic breadth, 44.5; across postorbital processes, 22.5; palatal 

 length, 37.6. (Merr. , 1. c.) 



b.—brumalis. [Mustehi), Bangs, Am. Nat., 1898, p. 502, fig. p. 503. 



Type locality. Okak, Labrador. 



Geogr. Distr. North Labrador. 



Gtnl. Char. Skull large, rostrum very short, broad; frontals 

 highly arched, auditory bullae very large and deep; dentition extremely 

 heavy throughout, the last upper molar in particular being very large; 

 the tooth row a good deal crowded. 



Color. No skin obtained. 



Measurements. Skull: basilar length of Hensel, 78.6; zygomatic 

 breadth, 51; mastoid breadth, 38.8; interorbital breadth, ig.6; breadth 

 between postorbital processes, 23.8; across canines, 17.2; greatest 

 length of auditory bulls, 17.2; single half of mandible, 58.4; front of 

 canine to back of last molar (upper jaw alveoli), 30.6. (Bangs, 1. c.) 



C. — actuosa. Osgood, N. Am. Faun., 1900, No. 19, p. 43. 



Type locality. Fort Yukon, Alaska. 



Geogr. Distr. Alaska. 



Genl. Char. Similar to 3f. a. bnimalis, but larger. Skull: audi- 

 tal bullae large and lengthened; dentition weaker; last upper molar 

 smaller. 



Color. Head, cheeks and throat pale grayish white mixed with 

 brown; ears whitish within, brown without; rest of upper parts pale 

 ochraceous buff; shoulders grayish; under parts similar to the upper, 

 chest darker; buffy white spot on breast; legs and feet dark brown; 

 tail brown, darkest at tip. 



Measurements. Total length, 665; tail vertebra, 223; hind foot, 

 109. Skull: occipito-nasal length, 85; zygomatic breadth, 55; across 

 postorbital processes, 24; palatal length, 44; length of audital 

 bullae, 19. 



