The Descent of Man

of the first coral- snake which I saw gliding
across a path in Brazil. Snakes coloured in this
peculiar manner, as Mr. Wallace states on the
authority of Dr. Gunther (62. 'Westminster Review,'
July 1st, 1867, p. 32.), are found nowhere
else in the world except in S. America, and here
no less than four genera occur. One of these,
Elaps, is venomous; a second and widelydistinct
genus is doubtfully venomous, and the
two others are quite harmless. The species belonging
to these distinct genera inhabit the same
districts, and are so like each other that no
one "but a naturalist would distinguish the
harmless from the poisonous kinds." Hence, as
Mr. Wallace believes, the innocuous kinds have
probably acquired their colours as a protection,
on the principle of imitation; for they would
naturally be thought dangerous by their enemies.
The cause, however, of the bright colours
of the venomous Elaps remains to be explained,
and this may perhaps be sexual selection.