Feb. i, 1899. NORTH AMERICAN MAMMALS ELLIOT. 227 



Characters. Belonging to the Boylii group, but of smaller 

 size and smaller ears and shorter tail than the majority of T. boylii 

 specimens. 



Color. Adult, male ; upper parts rich brownish-fulvous, bright- 

 est on the flanks ; dorsal area much darker, inclined to blackish; 

 flanks, under parts, legs, and feet pure white, making a strong 

 contrast between the upper and lower parts. Ears, furred out- 

 side at the base, same color as the head; rest of ears naked, pur- 

 plish-brown; an indistinct black ring around the eye ; tail, dark 

 brown above, pure white beneath. 



Cranial cliaracters. Compared with P. boylii, the skull has the 

 brain case less square, with a more gradual contraction at the 

 orbital region, and with comparatively longer nasals, auditory 

 bulls? much smaller, a narrower and shorter pterygoid fossa, 

 and slightly shorter palate, molars larger, tooth row, 4. mm. 



Measurements. Total length, 185 mm.; tail, 99; hind feet, 21 ; 

 ear, 15. The tails varies greatly in length among individuals, 

 ranging among the specimens before me from 89 to 112 mm. 



Remarks. The type described above is an old male, and repre- 

 sents only the color exhibited by any adult individual, and per- 

 haps on that account does not represent the species in its general 

 appearance as well as a younger animal would. The usual style 

 is much darker, the dorsal area almost black, and the side dark 

 buff, with little or none of the bright fulvous tint. In its gen- 

 eral aspect, it is a very dark mouse; with P. heeni, P. macrorboricus, 

 and -P. sitkensis, it does not seem comparable. 



Microtus morosus. 



Type. Boulder Lake, Challam Co., Olympic Mountains, Wash- 

 ington ; about 5,000 feet. Collected September n, 1898. 



Characters. Resembling somewhat M. serpens, Merr. from Brit- 

 ish Columbia, but not of so red a hue, and darker than M. bairdi 

 Merr. from Crater Lake, Oregon, as described, and differing 

 from both in having a longer and unicolor tail. 



Color. Upper parts dark brown, hairs tipped with fulvous, 

 this latter hue tinting the entire upper part of the body ; sides, 

 same as back ; under parts, plumbeous, with, in certain lights, 

 a silvery gloss ; feet and legs, brownish white ; ears, same color 

 as head and back, and almost hidden in fur ; tail dark brown, 

 changing to silvery in certain lights, with hardly any perceptible 

 difference between the upper and under sides. 



