54-8 Bulletin American Museum of Natural History. [Vol. XIX, 



19.5). These latter measurements are very close to those 

 given by Dr. Merriam for his E. orca from Prince William 

 Sound. 



It may prove that the larger Alaska coast specimens 

 (Yakutat north to Alaska Peninsula) are better referable to 

 E. dawsoni orca than to E. dawsoni. 



19. Microtus mordax vellerosus (Allen). WOOLLY VOLE. 



Microtus vellerosus ALLEN, Bull. Am. Mus. Nat. Hist., XII, 1899, 7. 

 March 4, 1899. Upper Liard River, Northwest Territory, Canada. 

 Microtus cautus ALLEN, ibid., Hell Gate, Liard River. 



Represented by 53 specimens collected as follows: Tele- 

 graph Creek, 38 specimens, July n to August 8, and October 

 1820; Cheonnee Mountains, i, July 24; Tahltan River, i, 

 August 18; Shesley River, i, August 27; Level Mountain, 6, 

 September 11-19; Raspberry Creek, 5, October 4-6; Sheep 

 Creek, i, October 14. About three-fifths are adult, of which 

 only 7 reach or exceed 190 mm., in total length. Of the 

 series of nearly 40 specimens from Telegraph Creek the 27 

 adults (6 males and 21 females) measure as follows: Males: 

 Total length, 175.3 (158190); tail vertebrae, 61.3 (5270); 

 hind foot, 20.8 (19-21); ear, 14 (13-15). Females: 176 (160- 

 195); 60.6 (50-70); 21 (19.5-21.5); 14 (13-15). Nine old 

 adults (7 males and 2 females) from the other localities mea- 

 sure slightly larger, as follows: Total length, 182.5 (168-202); 

 tail vertebras, 65 (60-70); hind foot, 20.7 (19.5-22); ear, 14 



(13-15). 



The series well illustrates the pelages of adults from July to 

 October, and of the young in various stages of growth. The 

 adults vary considerably in the amount of yellowish brown 

 suffusing the dorsal surface, even among specimens taken at 

 the same season and locality. July specimens have this tint 

 brighter and stronger, often reddish brown, than September 

 and October specimens, which are grayer and more yellowish 

 brown, but some October specimens have a rufescent brown 

 cast, while others are much paler and grayer. The type of 

 M. vellerosus is a very gray specimen from the upper Liard 



