GEOMYID#®—THOMOMYS TALPOIDES. 625 
Haxirat.—Supposed to occur in the Interior of North America, from 
“Fudson’s Bay” to the “Columbia River”, and to occupy about the northern 
half of the United States west of the Mississippi, exclusive of the Pacific 
Coast region; being replaced, to the west, by T. bu/bivorus, and, to the south, 
by T. umbrinus. (Undoubted specimens seen from Selkirk Settlement, British 
America; from Minnesota westward through Dakota and Montana to the 
Rocky Mountains; and from Idaho, Wyoming, Utah, and Nevada.) 
TaBLeE IL.—Measurements of eight fresh specimens of THOMOMYS TALPOIDES. 
i =] 
E From tip of nose to— ig Length of— 5 5 
q . 28 £ a 
= Locality. Collector. a5] os = e < 
S as oO S 2 ZS ° 
B Bale 9 id (Sl ang ORAM yes eA Tea 
3 4 é Pa a ais Z = s = 
Ss) ala |a|olala |e ||] Zi 
11515 | Souris River, Dakota....| Dr. E. Coues, U.S. A ..| & | 1.00 | 1.60 | 1.75 | 7.00 | 2.50 | 1.25 | 1.25 | 0.55 | Fresh. 
11517 9 | 0.75 | 1.40 | 1.60 | 6.25 | 2.75 | 1.15 | 1.25 | 0.55 |....do. 
11518 -| o& | 0.90 | 1.60 | 1.70) 7.50 |} 2.50 | 1.20 | 1.20 | 0.50 |....do. 
11520 |. -| & | 0.90 | 1.50 | 1.90 | 7.25 | 2.75 | 1.25 | 1.20 | 0.45 1. .--do. 
11522 co | 0.95 | 1.60 | 1.80 | 7.00 | 2.60 | 1.25 | 1.20 | 0.55 |....do. 
al Dr. C. E. McChesney, | ? | 0.72 | 1.36 | 1.63 | 6.30 | 1.84 1.09 | 1.09 | 0.50 |....do. 
U.S. A. 
PSE Sock Se eee eee esi oe do ..- ==-|-oh | 0.77 | 1.38 | 1.87) 7.00 | 1.87 | 1.17 | 1.17 | 0.47 |... do. 
Oo ||sose col lO cbse ssekescsasé |fssoscs flit See moeepeueces do | 0.84] 1.50] 1.81) 7.00 | 2.10 | 1.13 | 1.13 | 0,49 |....do, 
Nore.—The first five foregoing specimens, all adult, taken the same season (June to September, 1873), were carefully 
measured in the flesh by myself. Other specimens, from the same region, not measured in the flesh, carry the limits of tota, 
length from about 6 to about 8 inches, with a corresponding range of variation in other parts. The tail is taken from its 
trne base—it appears about half aninch shorter in the dried state. The weight of these specimens ranges from 6 to 7 ounces, 
The girth of the chest is about 5 inches; of the belly, 6.50. No.11517, 9, has 12 teats—2 pairs axillary, 2 pairs pectoral, 2 
pairs inguinal. When fully distended, in the fresh state, the width across the cheek-pouches is the greatest diameter of the 
body. Nos. 1, 2,54 (orig. nos.), all adult, were measured in the flesh by the collector, Dr. C. E. MeChesney, U.S.A. The 
measurements of tail seem to have been taken by him from its apparent base. 
The most northern specimen I have seen is from the Assiniboine River ; 
the species is supposed to range from Hudson’s Bay to the Rocky Mountains 
in British America (northern limit unknown). ‘In the United States, I have 
specimens from Minnesota, Dakota, Montana, Idaho, Nebraska, Wyoming, 
Nevada, and Utah. The southern limit is inferred to be somewhere along 
the middle of the United States. Its range may not inosculate with that of 
T. umbrinus ; at any rate, I have seen no intermediate specimens from any- 
where in the Interior, the approach to wmbrinus seeming to be made in the 
Pacific province, through budbivorus. True ¢alpoides exists fairly westward 
of the main chains of the Rocky Mountains; but no Thomomys of this style 
is known from immediate Pacific slopes. It meets and inosculates with the 
Northern style of budbivorus (“douglasi”) in the Columbia River region. 
This animal is elaborately described, and its synonymy fully discussed 
in the original memoir. 
40 M 
