152 RODENTS. 
Northern Pocket- The northern pocket-gopher (Thomonvys talpoides) is the best 
Gopher. known representative of a second genus, containing at least two 
species, and distinguished by the absence of grooves in the upper incisor teeth. 
This species measures from 6 to 8 inches in length, and the tail some 8 inches 
more; while its general colour is very similar to that of the brown rat. The 
animals of this genus are distributed over the whole of Canada and North America 
west of the Rocky Mountains. In habits they precisely resemble the preceding 
genus. 
THE KANGAROO-RATS. 
Genus Dipodomys. 
The kangaroo-rats and their smaller allies the pocket-mice are utterly unlike 
the pocket-gophers in external appearance, having elongated hind-limbs and tails, 









THE COMMON KANGAROO-RAT (3 nat. size). 
large eyes, and well-developed ears, while their habits resemble those of the 
jerboas. They agree, however, with the former in the possession of large external 
cheek-pouches, and their general internal structure, although their upper incisor 
teeth are proportionately much narrower, and there are certain peculiarities in the 
conformation of the skull. 
Common The kangaroo-rats are characterised by the molar teeth being 
Kangaroo-Rats. rootless, and their best known representative is the common species 
(Dipodomys phillipst) depicted in our illustration, which inhabits the desert 
regions to the eastward of the Rocky Mountains, and is characterised by the 
possession of four toes on the hind-feet. The head and body of this animal 
measure a little over 4 inches in length; while the tail is very long and tufted 
at the end, and the general build of the creature light and elegant. The colour of 
