INTRODUCTION. 



HE preceding Volume was occupied with a description of the FOUR- 

 HANDED, the WING-HANDED, the INSECT-EATING, the GNAWING, and 

 some of the FLESH-EATING animals ; the present exhibits the 

 remainder of them, together with those which are denominated the 

 K THICK-SKINNED, the RUMINATING, the TOOTHLESS, the Porni- 

 MKAKIXG, and the CETACEA. 



All these creatures, diversified as they are, present to the eye, 

 on a careful examination, a general resemblance. Distinguished by 

 an internal osseous framework, which yields to the body solidity and 

 support, they are called Vertebrata. Nor is this all ; for the body is 

 composed of a head, a trunk, and various limbs. The head, consisting of the skull which 

 incloses the brain, and of the face, which embraces the organs of sight, smell, hearing, and 

 taste, rests upon, or is attached to, the vertebral column, composed of a number of bones 

 movable upon one another, and unitedly forming a canal for the medulla oblonc/ata, or spinal 

 marrow. The limbs never exceed four, and are in pairs ; but sometimes one pair is wanting, 

 at others both; the blood is always warm and red; and, as a pre-eminently distinguishing 

 characteristic, the young are invariably fed with milk secreted by the mamma; of the mother. 

 And hence it was that Linnaeus arranged all these animals, with Man, their terrestrial 

 sovereign, at their head, into one CLASS, and called it MAMMALIA. 



Among them, it should be observed, are those not restricted to the shady woods, the 

 fruitful fields, the arid deserts, the shallow burrows, or the deep caverns of the earth, to which 

 the four extremities of the body are specially adapted. For some, like the seal and the 

 walrus, have the limbs formed expressly for swimming, and a life more or less aquatic, as 

 water is their usual abode ; though they occasionally land on the shore to bask in the sunbeams, 

 climb rocks or masses of ice, upon which for days they play their gambols or take their repose, 

 and then return to the fissures, or deep caves, of the cliffs, where they bring forth and rear 

 their young. Yet, as the head is separated from the body by a distinct neck, and hair or 

 fur is more or less the covering of the skin, their proper place as among the Mammalia is 

 at once determined. 



There are others, however, possessing very different characteristics, and . adapted to live 

 exclusively in the ocean. According to Ovid : 



" On every side above the waves they spring, 

 And showers of spray in gamesome frolic fling 

 Again they rise in light, attain they sweep 

 Beneath the briny waters of the deep ; 

 And joining bands a.s if in mimic play, 

 The winding measures of the dance essay, 

 And toss their sportive forms, and snort, and blow, 

 And streams of brine through widened nostrils throw/' 



