In like manner, the rise and fall of the tide probably answer to the periodical inundations; and thus the same effects are produced under apparently different but really similar circumstances.

The origin, however, of these coatings of metallic oxides, which seem as if cemented to the rocks, is not understood; and no reason, I believe, can be assigned for their thickness remaining the same.
(PLATE 5.

DIODON MACULATUS (DISTENDED AND CONTRACTED).) One day I was amused by watching the habits of the Diodon antennatus, which was caught swimming near the shore.

This fish, with its flabby skin, is well known to possess the singular power of distending itself into a nearly spherical form.

After having been taken out of water for a short time, and then again immersed in it, a considerable quantity both of water and air is absorbed by the mouth, and perhaps likewise by the branchial orifices.