Aristotle's History of Animals / In Ten Books

by Aristotle

3. The compact species are weaker than those which are thin, because their point of attachment is smaller. It is affirmed that the sponge possesses sensation; this is a proof of it, that it contracts if it perceives any purpose of tearing it up, and renders the task more difficult. The sponge does the same thing when the winds and waves are violent, that it may not lose its point of attachment. There are some persons who dispute this, as the natives of Torona. The sponge is inhabited by worms and other living creatures, which the rock-fish eat when the sponge is torn up, as well as the remainder of its roots. But if the sponge is broken off, it grows again, and is completed from the portion that is left.

4. The thin sponges are the largest, and they are most abundant on the Lycian coast; the compact sponges are softer, and the Achillean are more harsh than the others. On the whole, those that inhabit deep places with a mild temperature are the softest, for wind and cold weather harden them, as they do other growing things, and stop their increase. For this reason the sponges of the Hellespont are rough and compact; and, altogether, those beyond Malea, and those on this side, differ in softness and hardness.

5. Neither should the heat be very great, for the sponge becomes rotten, like plants, wherefore those near the shore are the best, especially if the water is deep near the land, for the temperature is moderated by the depth. When alive, before they are washed, they are black. Their point of attachment is neither single nor dispersed over the whole surface, for there are empty passages between the points of attachment. Something like a membrane is extended over their lower part, and the attachment is by several points; on the upper part are other closed passages, and four or five which are apparent. Wherefore some persons say that these are the organs by which they take their food.

6. There is also another species called aplysia, because it cannot be washed. This has very large passages; but the other parts of the substance are quite compact. When cut open it is more compact and smooth than the sponge, and the whole is like a lung; of all the sponges this one is confessed to have the most sensation, and to be the most enduring. They are plainly seen in the sea near the sponges, for the other sponges are white as the mud settles down upon them, but these are always black. This is the mode of production in sponges and testacea.

Chapter XV.

1. Among the malacostraca the carabi are impregnated by sexual intercourse, and contain their ova during three months, May, June, and July. They afterwards deposit them upon the hollow part of their folded tail, and their ova grow like worms. The same thing takes place in the malacia and oviparous fish, for their ova always grow.

2. The ova of the carabi are sandy, and divided into eight parts; for a cartilaginous appendage, round which the ova are attached, is united to each of the opercula at their junction with the side; and the whole resembles a bunch of grapes, for every one of the cartilaginous appendages is frequently subdivided, and the divisions are apparent to any one who will separate them, but when first seen they appear to be united. Those ova which are in the centre are larger than those which are contiguous to the perforation, and the last are the least.

3. The smallest ova are as large as millet; the ova are not continuous with the perforation, but in the middle. For two divisions extend on each side, from the tail and from the thorax, and this is also the line of junction for the opercula. The ova, which are placed at the side, cannot be enclosed, unless the extremity of the tail is drawn over them; this, however, covers them like a lid.

4. The female, in depositing her ova, appears to collect them on the cartilaginous appendages by means of the broad part of the folded tail. She produces them by pressing with her tail and bending her body. These cartilaginous processes at the season of oviposition increase in size, in order to become appropriate receptacles for the ova. The ova are deposited on these processes, as those of the sepia are deposited upon broken pieces of wood or anything floating in the sea. This is the manner of depositing them; but after they have been ripened twenty days, they are cast off altogether in a mass, as they appear when separated from the parent; in fifteen days, at the outside, the carabi are produced from these ova, and they are often taken off less than a finger's length. The ova are produced before Arcturus, and after Arcturus they are cast off.

5. The cyphæ among the carides contain their ova about four months. The carabi are found in rough and rocky places, the astaci in those that are smooth; but neither of them inhabit mud. For this cause the astaci are found in the Hellespont and near Thasus; the carabi in the neighbourhood of Sigeum and Athos. Fishermen, when they pursue their calling in the open sea, distinguish the rough and muddy places by the nature of the shore, and other signs. In the spring and winter they come near the shore; in summer time they go into deep water, sometimes for the sake of warmth, and sometimes for the cold.