34: 



VEUTEIHIATA. 



Class I. UIAIfOIAL,IA. 



The highest boon conferred upon the lower animals 

 is parental affection. The cold-blooded ovipara, reptiles 

 and fishes, unable to assist in the maturation of their off- 

 spring, are compelled to leave their eggs to be hatched by 

 the agency of external circumstances, and their progeny, even from the moment of their birth, arc 

 usually abandoned to chance and their own resources for protection and nourishment. In birds, the 

 duties and the pleasures inseparable from the necessity of incubating their ova, and of providing 

 nutriment for their callow brood, are indeed manifested to an extent altogether unparalleled in th< 

 lower order of vertebrate animals ; but it is to the mammals alone, the most sagacious and intelli- 

 gent of all the inhabitants of the earth, that the Creator has permitted the full enjoyment of pater- 

 nal and maternal love. It is in respect to these alone that he has cast the offspring absolutely 

 helpless and dependent on a mother's care and solicitude, thus conferring upon the parent the joys 

 and comforts that a mother oidy knows, the dearest, purest, and sweetest bestowed upon the ani- 

 mal creation.* 



The grand circumstance, therefore, by which this class of beings, designated under the title of 

 Mammalia, may be distinguished from all other members of the animal kingdom is, that the 

 females of every species are furnished with mammary (/lands — organs designed to supply a secre- 

 tion called milk, whereby the young are nourished from the moment of their birth, until they 

 have reached a sufficient age to enable them to live upon such animal or vegetable food as may he 

 adapted to their mature condition. The possession of these lactiferous glands is the great and 

 decisive characteristic of the class; to this, however, it may be added, that their visceral cavity b 

 separated into a thorax and abdomen by a muscular diaphragm, and that they breathe by means 

 of lungs similar to our own. Of their internal structure, we shall give a more detailed example 

 when we come to describe the human specie i 



The mammalia are very widely distributed over the earth. Most of them are terrestrial in their 

 habits, either browsing the herbage from the ground, or, if carnivorous, leading a life of rapine, by 

 carrying on an incessant and destructive warfare against animals inferior to themselves in strength 



* Jones's ''Structure of the Animal Kingdom." 



