Aristotle's History of Animals / In Ten Books

by Aristotle

5. The small ones are pounded up, shells and all, for it is not easy to separate them; but they separate the larger kinds from the shells, and then extract the pigment. For this purpose the mecon is divided from the neck, for the pigment lies above the part called the stomach, and when this is taken away, they are divided asunder. They are careful to bruise them while alive, for if they die before they are cut up, they vomit up the pigment; for this reason they keep them in the baskets till a sufficient number is collected, and there is time to procure the pigment.

6. The ancients did not let down or fasten any basket-net to their baits, so that it often happened that the purpura fell off as they were drawn up; but at the present time they use basket-nets, in order that if the purpura should fall off, it may not be lost. They are most likely to fall off when full, but when empty it is difficult to draw them from the bait. These are the peculiarities of the purpura. The nature of the ceryx is the same as that of the purpura, and so are their seasons.

7. They both have opercula, and so have all turbinated shell-fish, from the period of their birth. They feed by forcing out their tongue, as it is called, beneath the operculum: the purpura has a tongue larger than a finger, with which it feeds upon and pierces the conchylia, and even the shells of its own species. Both the purpura and the ceryx are long-lived, for the purpura lives six years, and its annual increase is seen in the divisions on the helix of its shell.

8. The mya also deposits nidamental capsules; those which are called limnostrea are the first to originate in muddy places, but the conchæ, chemæ, solens, and pectens find their subsistence in sandy shores; the pinnæ grow up from their byssus both in sandy and muddy shores. The pinnæ always contain a pinnophylax, either like a small caris or cancer, and soon die when this is extracted. On the whole, all the testacea are produced spontaneously in mud different kinds originating in different sorts of mud: the ostrea is found in mud, the conchæ and others that have been mentioned in sand. The tethya, balanus, and others which live on the surface, as the patella and nerita, originate in holes in the rocks. All these reach maturity very soon, especially the purpuræ and pectens, for they are matured in one year.

9. Very small white cancri are produced in some of the testacea, especially in the myæ that inhabit muddy places, and next to this in the pinnæ those which are called pinnoteræ; they occur also in the pectens and limnostrea. These animals apparently never grow; and the fishermen say that they are produced at the same time as the creatures they inhabit. The pectens disappear for some time in the sand, and so do the purpuræ. The ostrea (bivalves) are produced in the manner described, for some of them originate in shallow water, others near the shore, or among rocks, or in rough hard places, or in sand; and some have the power of locomotion, others have not.

10. Among those that are not locomotive, the pinnæ are fixed; the solens and conchæ remain on one spot, though not fixed, and do not survive separation from their home. The nature of the aster[165] is so hot, that if it is captured immediately after swallowing anything, its food is found digested; and they say that it is very troublesome in the Pyrrhæan Euripus. Its form is like the paintings of a star. The creatures called pneumones are spontaneously produced. The shell which painters use is very thick, and the pigment is produced on the outside of the shell; they are principally found in the neighbourhood of Caria.

11. The carcinium also originates in earth and mud, and afterwards makes its way into an empty shell, and when it grows too large for that, it leaves it for a larger one, as the shell of the nerita, strombus, and such like; it frequently occurs in the small ceryx. When it has entered the shell, it carries it about and lives in it, except that as it grows it migrates into a larger shell.

Chapter XIV.

1. The nature of the testacea is the same as that of creatures without shells, as the cnidæ[166] and sponges, which inhabit the holes in rocks. There are two kinds of cnidæ, some which live in holes in the rocks, and cannot be separated from them, and other migrating species which live upon the smooth flat surface of the rocks. (The patella also is free and locomotive.) In the interior of the sponges are found the creatures called pinnophylaces, and the interior is closed with a net like a spider's web, and small fish are captured by opening and closing this web, for it opens as they approach, and closes upon them when they have entered.

2. There are three kinds of sponges; one of them is thin, the other is thick, and the third, which is called the Achillean sponge, is slender, compact, and very strong; it is placed beneath helmets and thigh-pieces, for the sake of deadening the sound of blows; this kind is very rare. Among the compact kinds, those which are very hard and rough are called tragi. They all grow upon the rock or near the shore, and obtain their food from the mud. This is evident, for they are full of mud when they are captured. This is the case with all other fixed things, that they derive their food from the spot to which they are attached.