84 U. S. p. R. R. EXP. AND SURVEYS 47TH PARALLEL. 



This drowned itself in a pail of water. At this time there was ice formed every night at 

 our camp. 



The second specimen I obtained was also found drowned in a pail of water at our camp on 

 the great Sjiokan Plain, October 31, 1853. There being no trees within many miles of us, this 

 species probably lives entirely among the grass of the prairies. As we had snow and severe 

 frosts at that time, it probably remains active all winter. 



HESPEROMYS BOYLII, Baird. 



Long Tailed Jtfoase. 



Baird, Gen. Rep. Mammals, 1857, 471. 



Sp. Ch. — Bodf stout. Ears very large, almost naked. Tail stout, considerably longer than head and body, with long hairs 

 at the end, and 32 vertebrEB. Above, mixed brown and yellowish brown ; paler on the sides. Outside of fore leg colored to 

 the wrist. 



One specimen was collected at Shoalwater Bay, Washington Territory. 



HESPEROMYS CALTFORNICUS. 



Mus californicus, Gamble, Pr. A. N. So. Phila. IV, August, 1848, 78, (Monterey.) 

 Hespiromys californicus, Baird, Gen. Rep. Mammals, 1857, 478. 



Sp. Ch. — Very large. Size of a third grown rat. Ears very long, angular. Tail ratlier longer than body. Color above, 

 sooty brown, passing on the sides to fulvous. Under parts white, tinged with fulvous and ashy. Feet white. Tail brown, 

 a littler darker on the dorsal line. Soles entirely naked. 



In a trap set for wood rats I caught, one night, a mouse, which though very similar in 

 proportions and appearance to the rat, proved to be quite different, and even of another genus. 

 I afterwards got two more of them from an old rat's nest that I burned down. There were 

 three or four in it, and they remained until there was scarcely a stick unburnt before deserting 

 it. No rats were in this nest, and I have always found that not more than one or two of those 

 surrounding a tree were inhabited by them, the rest having a dilapidated appearance, and being 

 left to their smaller relatives, these wood mice and field mice. 



Of the habits of this wood mouse I know nothing further. They probibly much resemble 

 those'of the numerous species found in the United States. I may remark here that up to my 

 departure from California, on December 1, I saw no signs of hybernation of any of the small 

 rodentia, except a striped squirrel, which I only saw out once, and having watched often 

 afterward, concluded it had retired for the winter. There was then very little frost. 



Dimensions. — Nose to tail, 4| inches. Tail, 4J. Hind foot, 1 inch. Fore foot to wrist, ^ 

 inch. Ear, f inch long, | wide. 



NEOTOMA FQSCIPES, Cooper, Mss. 



Baird, Gen. Rep. Mammals, 1857, 495. (From Mss. of J. G. Cooper.) 



Sp. Ch. — Larger than the house rat (Mus decumanus). Tail nearly as long as the head and body, compressed at tip 

 Color above, yellowish rusty brown, lined with black. Beneath, soiled white. Hands and toes of hind feet white ; the 

 upper part of metatarsus dusky. Tail uniformly dusky all round. 



I found the wood rat of California extremely common in all those parts of Santa Clara valley 

 more or less covered with groves of oak and different shrubs. Almo.st every tree, either of the 

 evergreen or deciduous species of oak, had from one to six of their buildings under it. These 

 are built of short sticks, chips, and sometimes bones, piled with such skill as to shed rain — the 

 upper layers projecting downwards. Their form is conical, and height generally from four to five 

 feet, having about six entrances at the ground, and burrows extending beneath it as a retreat 



