210 ORDERS OF MAMMALIA* 



very solid substances ; and they frequently feed u}K)n woody 

 fibres and the bark of roots and trees. Of this order, among 

 others, are the beaver, the squirrel, and the various species 

 of hare and rabbit. Beavers are aquatic animals, and they 

 construct themselves habitations upon waters which are suf- 

 ficiently deep never to be frozen to the bottom. 



The fifth order {Eclenta'ta, toothless) are remarkable for 

 a great degree of torpor, listlessness, and indisposition to 

 motion ; but some more than others. The sloth, the ant- 

 cater, and the armadillo are among them, and of each of 

 tlrese there are several species. The three-toed sloth is an 

 animal whose very aspect is painful and disgusting. The 

 expression of its countenance, and its whole attitude, indeed, 

 convey to the beholder the impression, that its very existence 

 is a burden. 



Ruminating animals form the sixth order of this class, and 

 examples may be found in the camel, antelope, deer, ox, and 

 sheep. They have been more valuable to man than any 

 others. Their flesh furnishes a large proportion of our ani- 

 mal food. They are mild, docile, and easily domesticated. 



The seventh order {Pachyder'mata, thick-skinned) em- 

 braces ail the animals w ith hoofs which do not ruminate, as 

 the elephant, the tapir, the horse. The Hippopot'amus, or 

 River-Horse, inhabits principally the rivers of the south of 

 Africa. It walks with ease at the bottom of the water, though 

 obliged, occcasionally, to rise to the surface for breath. 



Animals of the whale kind, or cetaceous animals, form the 

 eighth order. They are usually confounded with the class 

 of fishes, which they resemble in many particulars of exter- 

 nal appearance, as well as in the circumstance of residing 

 always in the water. In point of structure, however, they 

 clearly belong to the present class, since they breathe air by 

 means of lungs, are warm-blooded, produce their young alive, 

 and nourish them with milk. 



The Marsii' pial animals, which form the ninth order, are 

 distinguished from all others by the possession of a recep- 

 tacle, formed by a duplicature of the skin, for the purpose 

 of holding their young, or of receiving them on the approach 

 of danger. Such are the Kanguroo and Opossum. 



Questions. — 1. By what are animals of the class Mammalia dis- 

 tinguished ? 2. Why is man, as an object of natural history, arranged 

 with this class ? 3. From a regard to what parts of animals of thif 



