1915.] 



THOMOMYS TALPOIDES GEOUP. 



99 



(November to May) : Bright buffy gray above, fading to paler buffy 

 in spring. Young: Upperparts duller, more plumbeous, fading to 

 buffy when haK grown, changing to dark fall pelage in October. 

 [See section on molt (p. 18); also five molts shown on one animal in 

 fig. 3, No. 1.] 



ShuU. — ^Long and straight, with shallow rostrum and strongly 

 developed and approximately parallel temporal ridges; nasals long 

 and truncate or rounded at posterior tip; bullae long and rather narrow 

 (becoming very narrow in specimens from the eastern part of the 

 range), basioccipital with wide, heavy shaft between bullae; auditory 

 meatus slender. Dentition: Molars heavy; incisors decurved at right 

 angle to axis of skull. 



Measurements. — Adult male from near Fort Clark, N. Dak. : Total 

 length, 240; tail vertebra, 70; hind foot, 31. Adult female from same 

 locality: 230, 70, 31. SJcull (of adult male from near Fort Clark): 

 Basal length, 40; nasals, 15.5; zygomatic breadth, 25; mastoid 

 breadth, 22; interorbital breadth, 7; alveolar length of upper molar 

 series, 8. 



Remarlcs. — There is now ample material from the type locality and 

 its general region to show the characters of rufescens, which proves to 

 be the large, dark-colored gopher occupymg the greater part of 

 North Dakota, eastern South Dakota, and southwestern Manitoba. 

 Specimens from the type region in early winter fur (November or 

 December) are still needed to complete our knowledge of seasonal 

 variation in pelage, but this pelage wiU probably be found to agree, 

 as do most other characters, with specimens from the eastern part of 

 the State. 



The type, a mounted specimen with skull inside, much faded but 

 otherwise in good condition, is in the American Museum of Natural 

 History. It has been removed from the base, and the old label, once 

 tacked on the base, is now attached to the foot. It bears the legend 

 TJionaomys rufescens Wied. Machtohpka indigen" and also ''Mas 

 Missouri," not very legible. It hardly seemed necessary to remove 

 the skull from so old and fragile a specimen, as there are good topo- 

 types, and the general size and large claws are good characters. The 

 hind foot measures 30 mm., dry. It is marked " " on the museum 

 label, which also is attached to the foot. 



Syeciraens examined. — Total number, 159, as follows: 

 Manitoba: Aweme, 4; Carbeny, 11; Selkirk Settlement, 1. 

 North Dakota: Bismarck, 4; Bottineau, 1; Braddock, 1; Cannonball River, 6; 

 De\ils Lake, 1; Dickinson, 2; Fish Lake (in Tm-tle Mountains), 8; Fort Clark, 

 5; Fort Rice, 1; Glen UlHn, 1; Grafton, 3; Hensler, 6; Jamestown, 6; Lari- 

 more, 7; Mandan, 10; Mnnewauken, 3; Minot, 1; Oakdale, 8; Pembina, 25; 

 Portland, 1; Sherbrooke, 6; Souris River, 2; Steel 1; Streeter, 2; Stump 

 Lake, 1; Valley City, 9; Wade, 2; Walhalla, 2; Washburn, 3. 

 South Dakota: Aberdeen, 2; Armour, 3; Fort Randall, 2; Fort Sisseton, 3; 

 Highmore, 1; Pierre, 3; TMiite Lake, 1, 



