THE AFRICAN FLYING SQUIRRELS 1241 



The number of genera of Rodents is so great that in a work like the present it is 

 only possible to notice some of the leading and more generally interesting types. 



The whole of the Rodents are almost entirely herbivorous in their habits, 

 and all of them obtain their food by gnawing. We have already noticed that 

 while the majority are terrestrial and burrowing, some are arboreal, others aquatic, 

 and a few endowed with the power of spurious flight; and it may be added that 

 of the terrestrial forms the hares are among the fleetest runners of all Mammals, 

 while the jerboas and chinchillas are distinguished by their leaping powers. They 

 are mostly harmless and inoffensive creatures, fleeing with the greatest terror and 

 precipitancy from the smallest of foes; but a few, like the common rat, when driven 

 to bay, will defend themselves desperately, and will then inflict comparatively severe 

 bites with their powerful front teeth. 



Many Rodents yield furs which are very largely used in commerce, 



although of less intrinsic value than those of many other Mammals. 



The flesh of hares and rabbits is largely consumed in Europe, while that of other 



members of the order is also eaten in various parts of the world; but the strong odor 



which characterizes many Rodents renders their flesh more or less unpalatable. 



As a whole, Rodents are characterized by their dull and frequently 

 uniform coloration, although there are many exceptions to this. 

 Indeed, many of the squirrels from the warmer regions of the globe, as well as one 

 of the species of marmot, are among the most brilliantly colored of all animals. 

 In the brighter-colored forms it does not appear that any rule can be laid down as to 

 the plan of coloration. Thus while in many of the squirrels the brilliant colors 

 take the form of distinct patches, distributed over various parts of the body, in the 

 palm-squirrels and ground-squirrels there are light longitudinal stripes on a dark 

 ground, and in the pacas there are light-colored spots. It appears, however, that 

 no Rodent exhibits transverse bars of different colors on the body, and in none is 

 the tail ornamented with alternate light and dark rings. 



The tail is very variable, being totally wanting in the guinea pig, 

 while in the jerboas it attains an enormous relative length. 



THE AFRICAN FLYING SQUIRRELS 

 Family ANOMALURID^ 



The true flying squirrels are confined to Asia, Europe, and North America, but 

 Africa possesses a group of somewhat similar animals which differ so decidedly in 

 structure that they are assigned to a distinct family. 



Before considering these animals in detail, a few words are necessary as to the 

 leading characteristics common to all the Rodents treated of in the present chapter, 

 which are collectively spoken of as the squirrel-like Rodents, or, technically, as the 

 Sciuromorpha. Together with the mouse-like Rodents described in the following 

 chapter, all these animals are characterized by the angular process of the lower 

 jaw* taking its origin from the root of the sheath of the incisor tooth. The 



* This is the projecting process seen at the hinder extremity of the lower jaw in the skull figured on p. 1239. 



