This slug, when disturbed, emits a very fine purplish-red fluid, which stains the water for the space of a foot around.

Besides this means of defence, an acrid secretion, which is spread over its body, causes a sharp, stinging sensation, similar to that produced by the Physalia, or Portuguese man-of-war.
I was much interested, on several occasions, by watching the habits of an Octopus, or cuttle-fish.

Although common in the pools of water left by the retiring tide, these animals were not easily caught.

By means of their long arms and suckers, they could drag their bodies into very narrow crevices; and when thus fixed, it required great force to remove them.

At other times they darted tail first, with the rapidity of an arrow, from one side of the pool to the other, at the same instant discolouring the water with a dark chestnut-brown ink.