FAMILY CHARACTERISTICS. 109 
CHAPTER VIII. 
FAMILY CHARACTERISTICS. 
Ler us proceed to a careful examination of 
the natural groups of animals called Families 
by naturalists, —a subject already briefly alluded 
to in a previous chapter. Families are natu- 
ral assemblages of animals less extensive than 
Orders, but, like Orders, Classes, and Branches, | 
founded upon certain categories of structure, 
as distinct for this kind of group as are those 
above specified for the other divisions in the 
classification of the Animal Kingdom, which we 
have thus far examined. 
That we may understand the true meaning 
of these divisions, we must not be misled by the 
name given by naturalists to this kind of groups. 
Here, as in so many other instances, a word 
already familiar, and as it were identified with 
the special sense in which it had been used, 
was adopted by science, and received a new sig- 
nification. When naturalists speak of Families 
among animals, they do not allude to the proge- 
ny of a known stock, as we designate, in com- 
