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CHAP. XIV.] THE NEOTROPICAL REGION. 29
birds with silky plumage peculiar to the Amazon valley. They
are often kept in houses, where they get very tame and affec-
tionate ; and they are useful in catching flies and other house
insects, which they do with great perseverance and dexterity.
Islands of Tropical South America.
These are few in number, and, with one exception, not of
much interest. Such islands as Trinidad and Sta. Catherina
form parts of South America, and have no peculiar groups of
animals. The small islands of Fernando Noronha, Trinidad,
and Martin Vaz, off the coast of Brazil, are the only Atlantic
islands somewhat remote from land ;
while the Galapagos Archi-
pelago in the Pacific is the only group whose productions have been
carefuUy examined, or which present features of special interest.
Galapagos Islands.—These are situated on the equator, about
500 miles from the coast of Ecuador. They consist of the large
Albemarle island, 70 miles long ; four much smaller (18 to 25
miles long), named Narborough, James, Indefatigable, and Chatham
Islands; four smaller stiU (9 to 12 miles long), named
Abingdon, Bindloes, Hood's, and Charles Islands. All are vol-
canic, and consist of fields of black basaltic lava, with great
numbers of extinct craters, a few which are still active. The
islands vary in height from 1,700 to 5,000 feet, and they all rise
sufficiently high to enter the region of moist currents of air, so
that while the lower parts are parched and excessively sterile,
above 800 or 1,000 feet there is a belt of comparatively green
and fertile country.
These islands are known to support 58 species of Vertebrates,
—1 quadruped, 52 birds and 5 reptiles, the greater part of which
are found nowhere else, while a considerable number belong to
peculiar and very remarkable genera. We must therefore notice
them in some detail.
Mammalia.—This class is represented by a mouse belonging
to the American genus Hesperomys, but slightly different from
any found on the continent. A true rat (Mus), slightly dif-
fering from any European species, also occurs ; and as there can
be little doubt that this is an escape from a ship, somewhat