SECTION A 



COMPARATIVE ANATOMY AND MORPHOLOGY 

 OF EUTHERIAN MAMMALS 



CHAPTER II 



THE MAMMALIA: AND THE APPLICATION OF THE METHODS 

 OF MORPHOLOGY TO THEIR CLASSIFICATION 



It is necessary at the outset to give a brief description of the 

 animal forms with which we are chiefly concerned, and to treat of 

 them in a methodical manner. 



Man's nearest relations are members of a class of vertebrate 

 animals called Mammalia. Of this class three sub-classes are 

 recognized, and it must be noted that the members of two of 

 these three sub-classes are comparatively few in number and not 

 natives of Europe ; an example of one of these sub-classes is the 

 Australian spiny ant-eater, and the kangaroo is an example of 

 the other. The third sub-class contains a larger number of animal 

 forms, and to it belong all our indigenous mammals. 



One can imagine several ways in which the various mammals 

 might be grouped for purposes of description : for instance, they 

 might be arranged according to their geographical distribution, 

 or else according to the nature of their food, or again according 

 to their habits : and the first-mentioned means of distinction 

 might be called a climatic criterion, which would for instance 

 distinguish arctic animals from those living in tropical latitudes, 



