CONCLUDING OBSERVATIONS. 355 
the first part of Chapter XII.) for flight in the air; while 
the fishes are so constructed (§ 353-357) as to swim eas- 
ily in the water. And then, in those classes of birds that 
are designed in part for life on the water, there are spe- 
cial provisions for swimming in their webbed feet and 
other arrangements (§ 291). Some animals are carnivo- 
rous, while others are herbivorous, and others still eat a 
variety of food, and may even be omnivorous, like man. 
The adaptation of organization in these different cases 
has reference, as you have seen, both to the kind of food 
and to the mode of obtaining it. If it had reference 
merely to the former, it would be seen only in the teeth, 
the jaw, and the stomach. But in its reference to the 
latter, it is observed in the structure and arrangement of 
the organs of the senses, and even of the whole frame. 
For example, in the carnivorous animal of prey, there 
must be a full development of the senses of sight, hear- 
ing, and smell; a frame capable of quick movement; 
strong claws, worked by stout muscles, to hold the prey ; 
teeth fitted to tear it in pieces, and a stomach altogether 
different from that of the herbivorous animals. 
619. The adaptations in relation to temperature are 
very interesting. Animals that live in cold climates have 
coverings which differ greatly from those of animals liv- 
ing in warm countries. The elephant, with his scanty 
hairs, is in strong contrast in this respect with the shag- 
gy-coated bear. Our supply of furs comes from north- 
ern regions, from animals that could not withstand the 
cold without such coverings. As the horse is a native 
of a warm climate, he requires the blanket in our winters, 
and for the same reason the cow and ox need to be bet- 
ter sheltered than is ordinarily done among the farmers 
of temperate climates. In the arctic regions, even ani- 
mals that are protected by a furry covering have also, as 
a farther defense against the ‘cold, a good layer of fat, 
which not only keeps the heat in by its non-conducting 
property, but also aids in the production of heat. We 
