84 
U. S. p. K. K. EXP. AND SUEVEYS — 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 Spokan 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 Mouse. 
Baird, Gen. Rep. Mammals, 1857, 471. 
Sp. Ch. — Body stout. Ears very large, almost naked. Tail stout, considerably longer than head and body, with long hairs 
at the end, and 32 vertebrte. 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 CALIFORNICUS. 
Mas californicus, Gamble, Pr. A. N. Sc. Phila. IV, August, 1848, 78, (Monterey.) 
Hesperomys californicus, Baird, Gen. Rep. Mammals, 1857, 478. 
Sp. Ch.— Very large. Size of a third grown rat. Ears very long, angular. Tail rather 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 probably 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, 4f . Hind foot, 1 inch. Fore foot to wrist, ^ 
inch. Ear, § inch long, f wide. 
NEOTOMA FQSCIPES, Cooper, Mss. 
Baird, Gen. Rep. Mammals, 1857, 495. (From Mss. of J. G. Cooper.) 
gp. Ch. — Larger than the house rat (J!/iis 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. Almost 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 
