GHOGRAPHICAL DISTRIBUTION. 66? 
2. Indian ‘region, with two provinces, viz. : 
a. Contjnental. 
6. Insular. 
V. South American Temperate realm, with two provinces, viz.: 
a, Andean, 
6. Pampean, 
VI. Australian realm, with three regions, viz. : 
1. Australian, with two provinces, viz. - 
a. Australian, 
b. Papuan, 
2. Polynesian. 
3. New Zealand, 
VII. Lemurian realm, undivided. 
e 
VIII. Antarctic or South Circumpolar, undivided. 
Migrations of Animals.—Intimateiy connected with zoogeog- 
raphy ars the migrations of animals, especially birds. Nearly all the 
birds of the United States which breed in the central and northern 
portions pass southward in the autumn, and winter in the Southern 
States or in Central America and’ the West Indies. Most of the birds 
which breed in Northern and Central Europe fly at the approach of 
cold weather into Southern Europe or across the Mediterranean into 
Northern Africa. The causes of this regular periodical migration are 
probably due, primarily, to the changes of the seasons and to the want 
of food in the colder portion of the year, and, secondarily, to the 
breeding habits of birds. 
The periodical migrations of fishes from deep to shoal water are 
connected with their breeding habits, the marine fish being in most 
cases compelled to spawn in rivers or in shoal-water. The migratory 
movements of fishes along the coast are probably connected with the 
presence or absence of their accustomed food. 
The partial, occasional migrations of locusts depend on the undue 
increase in the numbers of the insects, and the consequent lack of 
food, while the direction of the swarms is largely dependent on the 
general course and force of the winds. ai 
