There are various kinds of crabs, known as carabi, lobsters, maiæ, paguri, heracleotici, lions, and others of less note. The carabus differs from other crabs, in having a tail; in Phœnicia they are called hippoi, or horses, being of such extraordinary swiftness, that it is impossible to overtake them. Crabs are long-lived, and have eight feet, all of which are bent obliquely; besides which, the animal has two claws with indented pincers. The upper part only of these forefeet is movable: the right claw is the largest in them all. Sometimes they assemble together in large bodies; but as they are unable to cross the mouth of the Black Sea, they turn back again and go round by land, and the road by which they travel is to be seen all beaten down with their foot-marks.
The smallest crab known is the pinnotheres. It is peculiarly exposed to danger, but its shrewdness is evinced by its concealing itself in the shell of the oyster, removing as it grows larger, to those of a larger size.
Crabs, when alarmed, go backwards as swiftly as when moving forwards. They fight like rams, butting at each other with their horns. They have a mode of curing themselves of the bites of serpents. It is said, that while the sun is passing through the sign of Cancer, the dead bodies of the crabs, which are lying thrown up on the shore, are transformed into serpents.
To the same class also belongs the sea-urchin, which has spines in place of feet; its mode of moving along is to roll like a ball, hence it is that these animals are often found with their prickles rubbed off. Those among them which have the longest spines of all, are known by the name of echinometræ, while at the same time their body is the very smallest. They are not all of them of the same glassy color; in the vicinity of Torone they are white, with very short spines. The eggs of all of them are bitter, and are five in number; the mouth is situate in the middle of the body, and faces the earth. It is said that these creatures foreknow the approach of a storm at sea, and that they take up little stones with which they cover themselves, and so provide a sort of ballast against their volubility, for they are very unwilling by rolling along to wear away their prickles. As soon as seafaring persons observe this, they at once moor their ship with several anchors.