138 HABITS AND INSTINCTS OP ANIMALS. CHAP. V. 



every one knows that the different families of sand- 

 pipers, plovers, curlews, and couriers (Tachydromus 

 Orientalis Sw.*, fig.4>5.) 



45 $j^' are j f a ^ hirds, the swiftest 



runners in the whole circle 

 of ornithology. The same 

 principle of safety is seen 

 in the extensive family of 

 squirrels, with the addition 

 of another quality, that 

 of climbing with the great- 

 est agility among trees, and 

 of taking prodigious leaps from bough to bough ; they 

 run, in fact, like hares, but over a different surface, 

 and in a different direction : they are the hares of the 

 trees, instead of the ground ; and this principle is 

 carried so far among certain genera, that the quality of 

 leaping almost borders upon that of flying : hence, the 

 name of flying squirrels, given to such as have the skin, 

 between the legs, dilated into a thin membrane, suffi- 

 ciently wide to expand in the act of jumping, and of 

 supporting these animals in the air in the manner of an 

 umbrella or parachute. The porcupines have a dif- 

 ferent and a very peculiar mode of self-defence. Speed 

 does not belong to them, but they are armed with 

 acute spines, which they can raise or depress at 

 pleasure ; and one species can even shoot these spines, 

 as it is affirmed, into their foes. Most of the species 

 climb trees with much facility, for they are provided 

 with a prehensile tail. All these, however, have the 

 power of rolling themselves into a ball, erecting their 

 spines, and thereby presenting to their foes an un- 

 interrupted surface of spears. The power of throwing 

 the quills, as above mentioned, and attributed to the 

 European porcupine, has recently been denied ; but its 

 mode of defence is scarcely less formidable. It will 



* See the specific characters of the species composing this genus, in the 

 volume on Animals in Menageries, p. 339, 340. ; and Birds of Western 

 Africa, vol. ii. 



