THE CLASSIFICATION OF ANIMALS, 29% 
less and less importance, as we descend from the general 
to the special. 
Individuals are the units of the Animal Creation. An 
animal existence, complete in all its parts, is an individual, 
whether separate, as Man, or living in a community, as the 
Coral.” 
Variety: when two or more individuals differ by a sin- 
gle peculiarity only, such as size, color, or outline, one is 
called a variety of the other; as the various races of Men 
and breeds of Cattle. Varieties are usually local. A cross 
between distinct races is called mongrel. 
Species is the smallest group of individuals which can 
be defined by several constant characteristics. They are 
so alike, that it is possible for them to have descended 
from one pair; and they always transmit to their offspring 
some peculiarity of their organization. A cross between 
two distinct species, as the Horse and Ass, is called a hy- 
brid ; as the Mule. 
Genus is a group of species having the same essential 
structure. Thus, the closely allied species, Cat, Tiger, and 
Lion, belong to one genus. 
Family, or Tribe, is a group of genera having a simi- 
lar form. Thus, the Dogs and Foxes belong to different 
genera, but betray a family likeness. 
Order is a group of families, or genera, related to one 
another by a common structure. Cats, Dogs, Hyenas, and 
Bears are linked together by important anatomical feat- 
ures; their teeth, stomachs, and claws show carnivorous 
habits. 
Class is a still larger group, comprising all animals 
which agree simply in a special modification of the type 
to which they belong. Thus, Fishes, Amphibians, Rep- 
tiles, Birds, and Mammals are so many aspects of the Ver- 
tebrate type. 
Subkingdom is a primary division of the Animal King- 
