206 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



this particular locality to account for this Mouse selecting it as a resi- 

 dence I am unable to say; but it is certain that it has been secured no- 

 where else here. The location, to be sure, is favorable as regards water 

 and food, but njt more so in this respect than many other i)laces in the 

 immediate vicinity of the post. 



At Fort Berthold, Dakota Territory, on the Missouri Eiver, where I 

 resided during the greater part of the years 1872 and 1873, this Mouse is 

 very abundant. The Indians of that agency (Arickarees, Gros Ventres, 

 and Mandans) are united by the bond of hatred against the Sioux, 

 and were during these and many former years in an almost constant 

 state of war. In the incursions of the Sioux, many attemps have been 

 made to destroy the united village of the three tribes by fire, and one 

 attempt (in 1863) was partially successful. The three tribes found it 

 necessary, in consequence, to have some secure store-house for their pro- 

 duce, and finally adopted the cache method. The caches of these Indi- 

 ans, of which there are one or more to each lodge, are dug with great 

 care, and resemble in shape a funnel inverted, and have a capacity of 

 about seventy-five bushels. The opening, which would correspond with 

 the small end of the funnel, is carefully covered, first with boards, then 

 hay, and finally with earth, the latter of which is carefully trodden down, 

 raked over, and in a day or two all trace of the opening is obliterated. 

 Sometimes these caches are dug under the lodge of the owner, but much 

 more frequently on the outside of the village, and the exact place is 

 known to the owners only, and by means of alignment with permanent 

 landmarks. In these caches, which the Sioux have never yet succeeded 

 in finding, are stored their supplies of corn, beans, squash, and, of late 

 years, potatoes ; and in them the Missouri Mouse takes up his abode ; and 

 it is no uncommon thing for three or four to be killed at each opening 

 of the cache, which seldom occurs more than three times in each year. 



I have observed that the Missouri Mouse breeds here early in May 

 and August, and I believe but two litters are brought forth each year. 

 Lactation extends over a period of three weeks, at the end of which 

 time the young are fully able to care for themselves. 



DescrijJtion of specimen No. 204, collection of Dr. Chas. E. McChesney. 



This is a mature female specimen of large size, as will be seen by the 

 measurements given below. 



Upper parts light gray throughout ; under parts white. Fore legs 

 as under parts; on the outer part of hind legs the gray of the upper 

 parts extends the entire length of the femur. Inside of hind legs same 

 as under parts. 



Tail beneath white, above but little darker, sparsely haired to the 

 very tip. It will be noticed that the tail is short as compared with that 

 of H. leucopus. 



Ears well developed, sparsely haired inside and outside for about 

 jone-third of their height ; the hairs of the outer portion nearest the head 

 are black-tipped. 



