ORDER RODENTIA. 201 



genus most obviously, and at a glance ; but they are not 

 exclusively peculiar to it ; they are found also in the 

 Hedgehog, Tenrec, Echimys, and Echydnes. The Echi- 

 mys, however, which alone of these belongs to this order, 

 have the spines in shape like a sword-blade, and not cylin- 

 drical or tapering, as in the genus in question. 



The variations in organized creation are so numerous 

 that their mere observation becomes trite and useless ; the 

 business of natural history is not merely to find out and 

 observe them, but so to class and divide them by factitious 

 boundaries, founded on natural demarcations, that the 

 memory may be enabled the more readily to recal them at 

 command. The majority, however, of these countless 

 variations seem mere modifications of a much smaller 

 number of given types. Thus the different modifications of 

 the integuments and excrescences in animals, which are 

 almost as various as the genera, or even the species, may 

 all be referred to a very few sorts; hair, feathers, and scales 

 are found in the different classes, modified in an end- 

 less variety of modes ; and when the generality of these 

 integuments is considered, we are naturally surprised 

 to find something of a perfectly different character, but 

 limited to a very small number of unimportant creatures, 

 though differently modified in each species to which they 

 are proper. 



When the destinies of any given animal require particular 

 capabilities in any one direction, we generally find some one 

 organ fitted for the intended object, either modified or 

 greatly developed ; thus the mowing or cutting of grass, the 

 tearing or dividing of flesh, and the pounding or tritu- 

 rating of grain, are all performed by the same organs, the 

 teeth; nor in general, and but with a few exceptions, is 

 one order of quadrupeds furnished with any particular or- 

 gan, which may not be found, though differently modified, 

 in the other, 



