WHAT IS A “MAMMAL”? 
(Cinbeye aL ishike 30 
Characters of the Mammalia 
NACCURATE though the term undoubtedly is (for 
all ‘‘maimmals”’ do not possess mamme, 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 nota 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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