AN INTRODUCTION 
TO 
THE STUDY OF MAMMALS 
LIVING AND EXTINCT 
CHAPTER I 
INTRODUCTORY REMARKS 
Mamata (French, Mammiferes; German, Séiugethierc) is the name 
invented by Linnzus (from the Latin mamma), and now commonly 
used by zoologists, for one of the five great classes of vertebrated 
animals, which, though the best known and undoubtedly the most 
important group of the animal kingdom, has never received any 
generally accepted vernacular designation in our language. The 
unity of structure of the animals composing this class, and their 
definite demarcation from other vertebrates, were not recognised 
until comparatively modern times, and hence no word was thought 
of to designate what zoologists now term a mammal. The nearest 
equivalents in common use are “beast” and ‘quadruped,” both of 
which, however, cover a different ground, since they are often used 
to include the larger four-footed reptiles, and to exclude certain un- 
doubted mammals, as Man, Bats, and Whales. 
The limits of the class as now understood by zoologists are 
perfectly well defined, and, although certain forms still existing on 
the earth (but not those mentioned above as excluded by the popular 
idea) are of exceedingly aberrant structure, and exhibit several well- 
marked characters connecting them with the lower vertebrated 
groups, common consent retains them in the class with which the 
great proportion of their characters ally them, and hitherto no 
traces of any species showing still more divergent or transitional 
characters have been discovered. There is thus an interval, not 
bridged over by any known forms, between mammals and other 
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