ORDER RODEJSTIA; GENERAL CHARACTERS. 249 



Of this some extraordinary instances will be given, when the 

 Rat family is described. 



217. The animals composing this order are mostly of small 

 size, the Capylara ( 234), which is the largest, not equalling a 

 pig in bulk : but they are very numerous, and are widely 

 diffused over the globe. They are most abundant, and present 

 themselves in the greatest variety, in South America; whilst 

 they are the rarest in New Holland, which contains but six 

 known species of this order, its place being occupied in that 

 region by the rodent forms of the Marsupialia. The Rodentia 

 exhibit considerable variety of disposition ; some being very 

 docile and gentle, whilst others are savage and untameable : but 

 the former is certainly the general character of the group. Some 

 of them are remarkable for the high development of their 

 instinctive powers, but none of them exhibit any considerable de- 

 gree of sagacity (ANIM. PHYSIOL., Chap. XTY.) : and their brain, 

 in the nearly entire absence of convolutions, and in other charac- 

 ters, more resembles that of Birds than that of the higher 

 Mammalia. It has been justly remarked, that they are more 

 easily tamed than educated ; their intelligence not being sufficient 

 to enable them to learn. These animals usually multiply very 

 fast : they produce large litters several times a year ; and the 

 young speedily arrive at maturity, requiring, for the most part, 

 but little care on the part of their parents during the period of 

 infancy. This is one example, therefore, of the general prin- 

 ciple, the applications of which have been elsewhere dwelt 

 upon, that, the higher the development which is ultimately to be 

 attained by a Plant or Animal, the longer is the period of prepa- 

 ration for it, and the greater is the assistance which it needs 

 during its early state. With the exception of some remark- 

 able aberrant forms, there is a considerable similarity throughout 

 the whole group. Nearly all of them agree in the large size of 

 the posterior extremities, as compared with the anterior; and 

 this is sometimes almost as considerable as in the Kangaroos. Most 

 of them have the habit of sitting upon their haunches, and of 

 using their anterior members for the prehension of food, &c. ; 

 not, however, as in higher animals, by grasping it in either 



