But we have seen that at Bahia Blanca, which is four degrees southward, and therefore with a climate only a very little colder, this same temperature, with a rather less extreme heat, was sufficient to awake all orders of animated beings.

This shows how nicely the stimulus required to arouse hybernating animals is governed by the usual climate of the district, and not by the absolute heat.

It is well known that within the tropics the hybernation, or more properly aestivation, of animals is determined not by the temperature, but by the times of drought.

Near Rio de Janeiro, I was at first surprised to observe that, a few days after some little depressions had been filled with water, they were peopled by numerous full-grown shells and beetles, which must have been lying dormant.

Humboldt has related the strange accident of a hovel having been erected over a spot where a young crocodile lay buried in the hardened mud.