LE CONTE'S MOUSE. 69! 



The Florida Rat, Ncotouia Floridiana, has a light and agile form, 

 bearing some resemblance to that of the squirrel ; the eyes are large, the 

 ears thin and prominent ; the legs robust, The body and head are lead 

 color, intermixed with yellowish black hair. The border of the abdomen 

 is buff, the under surface of the body white. An adult specimen measures 

 eight inches from nose to root of tail. 



The Rat is found in all the States, but exhibits different habits in 

 different circumstances. In Florida it burrows under stones and in 

 rivers , in Georgia it prefers the woods. Sometimes it makes its nest in 

 the fork of a tree ; sometimes among vines near a sluggish stream. It 

 forms, by piling up dry sticks, grasses, mud, and leaves, a structure im- 

 pervious to rain, and inaccessible to the wild cat or racoon. The nests 

 they build in trees are often of enormous size. Audubon saw some in 

 Georgia ten to twenty feet from the ground which appeared larger than 

 a cart-wheel, and contained a mass of leaves and sticks that would have 

 more than filled a barrel. On the Missouri River, this rat lives in hollo\v 

 trees ; in the Rocky Mountains it nestles in clefts of the rock. In fact, it 

 makes itself at home everywhere. 



The Rocky Mountain Rat, Ncotoma Druimnondii, is larger than the 

 Florida Rat, and much more destructive. It gnaws everything left in its 

 way, and is hated by the fur-traders, for it will cut their blankets to 

 pieces while they ai'e asleep, and gnaw through whole packs of furs in a 

 single night. 



It is very common near the Columbia River, in Oregon, and along 

 the sides of the Rocky Mountains. 



GENUS REITHRODON. 



Le Conte's Mouse, Rcitlirodon Lc Contcs, is about half the size of a 

 full-grown mouse. The upper fore-teeth are deeply grooved, and yellow 

 in color. The ears round, moderate in size, and nearly naked. The nails 

 on the feet are long, but slightly hooked, and adapted to digging. The 

 specimen described by Audubon came from the State of Georgia. 



GENUS SIGMODON. 



This genus was formed by Messrs. Say and Ord, and comprises two 

 species which were previously placed among the Arvicolce. The name of 

 the genus is significative of its generic characteristic, namely, that the 

 molar of the upper jaw has the form of the Greek letter S or H. 



