214 NEW ZEALAND NATURE-STUDY BOOK 
XVIIL.—MAMMALS. 
INTRODUCTION. —The following are some of the characteristics 
which distinguish this class of vertebrates from the others we 
have been considering. 
(1) The young are nourished for a longer or shorter time by the 
milk or special secretion of the mammary glands. 
(2) Certain parts of the skin are at some period of life provided 
with a covering of hairs. 
(3) The crowns of the back teeth are frequently supported by 
from two to four roots. 
(4) Closely fitting caps of bone, known as epiphyses, are nearly 
always present at the ends of the centra of the vertebral column. 
These but loosely united in the young, become fused to the centra 
in the adult. 
The Rabbit: Classification. The Rabbit belongs to 
an order of mammals known as Rodents, so called from 
their habit of gnawing. This order includes Rats, Mice, 
Hares, Squirrels, ete. 
General description. The Rabbit is a small animal, 
about the size of a cat, with a long body and relatively small 
head. The outside of its body is almost entirely covered with 
a warm coat of fur, consisting of two kinds of hair—coarse 
and fine. The coarser hairs are longer and fewer in number 
than the fine ones, the latter being closcly-set over the body 
and protected by the former from damp and dirt. The long 
hairs, moreover, prevent the close soft hairs from becoming 
matted. 
It might be well here to note the difference between fur, 
hair, and wool. Fur is soft and fine, and its great warmth 
is due to the air which is enclosed between its close fine 
hairs. Hair on the other hand is loose and coarse, and is 
not so warm as either of the other two substances, | Wool 
is thick and matted, and like fur, is able to entangle a good 
deal of air—hence its warmth. Fur-bearing animals are 
generally exposed, owing to their method of life, to either 
