THE YOUNG NATUEALTST 



233 



is preserved in his collection. I have also 

 seen buff, cream, and white moles, but they 

 are rare. The burrowing habits of the mole 

 are well known, and although it disfigures 

 land by the hillocks it throws up, it renders 

 very great service by the number of insects 

 which it destroys, and will not stay in any 

 place when the supply of food falls short. 

 It also turns up fresh soil from below and 

 brings it to the surface, while its run 

 assists in draining the land. All the runs of 

 the mole are generally said to diverge from 

 a large mound, which is intersected by 

 circular runs and chambers, where it 

 builds its nest, and which is called the 

 mole's castle. Figures of this structure 

 are to be found in many introductory works 

 on Natural History, but we have no per- 

 sonal knowledge of it. 



12. RODENTIA [Lsit.rodens. gnawing).— 

 The Rodents are distinguished by two long, 

 sharp teeth in front both in the upper and 

 lower jaws, which enables the possessor to 

 gnaw hard substances like wood. In this 

 order we find such animals as the hare, 

 rabbit, rat, vole, mouse, and squirrel, and 

 in foreign countries the Alpine marmot and 

 porcupine. The rodents are numerous in 

 all quarters of the globe, some, like the 

 rabbit, having prodigious powers of increase. 



The Beaver belongs to this order. It is 

 now confined to North America and the 

 northern portion of the Old World, but 

 there is little doubt that it was formerly an 

 inhabitant of this country. It is chiefly 

 remarkable for the dams which it constructs 

 across running streams of considerable 

 width. These dams are made by a number 

 of the animals working together, and are 

 constructed of branches of trees, sticks, 

 stones, and mud ; intermixed with these are 

 branches gnawed from living willow and other 

 trees, and as some of these take root and 

 grow, and refuse matter brought down by the 

 stream is lodged, the whole in time becomes 

 a compact structure. These embankments 



have always a curviture against the stream, 

 except it be very slow, for the purpose, 

 apparently, of giving additional power of 

 resistance, and within are placed the houses 

 of the beavers, constructed of sticks and 

 mud, and having an entrance below the 

 water level. The beaver is hunted in winter 

 for the sake of his fine glossy coat. 



Another animal of this order is the 

 lemming, so numerous in the northern parts 

 of Scandinavia, and which migrate in such 

 vast swarms to and from the fells. 



The squirrels are an exceedingly interest- 

 ing and beautiful genus of animals. We 

 have only one species inthiscountry which is 

 generally of a rich red brown, though I have 

 seen varieties entirely black in Sherwood 

 Forest. Some of the American kinds are 

 larger than ours, and very beautiful, being 

 black, silvery grey, or golden grey ; some of 

 the ground squirrels are very small and con- 

 struct a burrow near the roots of trees. In the 

 Rocky Mountains are certain species called 

 flying squirrels, which have an extension of 

 skin between the fore and hind limbs, and a 

 flattened tail, They cannot ascend, and 

 therefore cannot really fly, but can take 

 very long leaps from one tree to another, 

 stretching out the legs and membrane at the 

 time, which enables them to sail like sea- 

 gulls for a considerable distance. 



The little harvest mouse, a native of the 

 Southern counties of England, and one of 

 the smallest mammals ; constructs a beauti- 

 ful round nest, suspended in the standing 

 corn. 



The English hares are grey brown, very 

 nearly the colour of the fallow-field. In 

 Scotland they are grey in summer, but in 

 winter when the ground is generally covered 

 with snow they change to pure white ; and 

 in the Arctic regions, where there is 

 perpetual snow, the hares are perpetually 

 white. I have seen one hare piebald. 



It is very strange that the present race of 

 rats, which were introduced probably from 



