4. They are taken in the spring, about the time that they deposit their capsules, but they are never taken during the dog-days, for then they do not feed, but conceal themselves and get out of the way. The pigment is contained between the mecon and the neck. The union of these parts is thick, and the colour is like a white membrane; this is taken away. When this is bruised, the pigment wets and stains the hand. Something resembling a vein passes through it, and this appears to be the pigment; the nature of the rest resembles alum.[164] The pigment is the worst at the period of depositing their nidamental capsules. [164] Evidently a corrupt reading. 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.