WHAT IS A "MAMMAL"? 



CHAPTER II 



Characters of the Mammalia 



INACCURATE though the term undoubtedly is (for 

 all "mammals" do not possess mammae, or teats) 

 in application from derivation, it is better to adhere, to 

 the expression in lieu of something better, than to use or 

 revert to the entirely wrong vernacular words in common 

 use, viz., " Quadrupeds," " Beasts," or " Animals." 

 For lizards are quadrupeds, and the converse of animal 

 is clearly vegetable or mineral. " Beasts " might be re- 

 tained, but that it has a somewhat insulting suggestion. 

 The justification of the term, however, is less important 

 than its meaning. What are we to understand by 

 mammals or mammalia ? For us who are concerned 

 here only with living mammals, the distinction from 

 other backboned animals is quite easy and obvious, even 

 without having recourse to bony and other structural 

 characters. By external form and character only, if 

 rightly put, it is within the power of any one to recognize 

 clearly the features which enable him to assert positively 

 that a given animal is or is not a mammal. It is, in the 

 first place, not correct to define mammals as quadrupedal; 

 most of them are so indeed, and all that especially con- 

 cern us in this place. But if we attempt to make 

 definitions that suit the entire " class," it is requisite to 

 allow for these exceptions. To begin with, man is not 



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