The curiosity and wonder which have been excited in mankind by this subject, will not allow me any longer to defer giving an account of the generation of these animals. Fishes couple by rubbing their bellies2767 against one another; an operation, however, that is performed with such extraordinary celerity as to escape the sight. Dolphins2768 also, and other animals of the cetaceous kind, couple in a similar manner, though the time occupied in so doing is somewhat longer. The female fish, at the season for coupling, follows the male, and strikes against its belly with its muzzle; while the male in its turn, when the female is about to spawn, follows it and devours2769 the eggs. But with them, the simple act of coupling is not sufficient2770 for the purposes of reproduction; it is necessary for the male to pass among the eggs which the female has produced, in order to sprinkle them with its vitalizing fluid. This does not, however, reach all the eggs out of so vast a multitude; indeed, if it did, the seas and lakes would soon be filled, seeing that each female produces these eggs in quantities innumerable.2771

(51.) The eggs2772 of fishes grow in the sea; some of them with the greatest rapidity, those of the muræna, for instance; others, again, somewhat more slowly. Those among the flat fishes,2773 whose tails or stings are not in the way, as well as those of the turtle kind, couple the one upon the other: the polypus by attaching one of its feelers to the nostrils2774 of the female, the sæpia and loligo, by means of the tongue; uniting the arms, they then swim contrary ways; these last also bring forth at the mouth. The polypi,2775 however, couple with the head downwards towards the ground, while the rest of the soft2776 fish couple backwards in the same manner as the dog; cray-fish and shrimps do the same, and crabs employ the mouth.

Frogs leap the one upon the other, the male with its fore-feet clasping the armpits of the female, and with its hinder ones the haunches. The female produces tiny pieces of black flesh, which are known by the name of gyrini,2777 and are only to be distinguished by the eyes and tail; very soon, however, the feet are developed, and the tail, becoming bifurcate, forms the hind legs. It is a most singular thing, but, after a life of six months’ duration, frogs melt away2778 into slime, though no one ever sees how it is done; after which they come to life again in the water during the spring, just as they were2779 before. This is effected by some occult operation of Nature, and happens regularly every year.

Mussels, also, and scallops are produced in the sand by the spontaneous2780 operations of nature. Those which have a harder shell, such as the murex and the purple, are formed from a viscous fluid like saliva, just as gnats are produced from liquids turned sour,2781 and the fish called the apua,2782 from the foam of the sea when warm, after the fall of a shower.

Those fish, again, which are covered with a stony coat, such as the oyster, are produced from mud in a putrid state, or else from the foam that has collected around ships which have been lying for a long time in the same position, about posts driven into the earth, and more especially around logs of wood.2783 It has been discovered, of late years, in the oyster-beds,2784 that the animal discharges an impregnating liquid,2785 which has the appearance of milk. Eels, again, rub themselves against rocks, upon which, the particles2786 which they thus scrape from off their bodies come to life, such being their only means of reproduction. The various kinds of fishes do not couple out of their own kind, with the exception of the squatina and the ray.2787 The fish that is produced from the union of these two, resembles a ray in the fore part, and bears a name among the Greeks compounded of the two.2788

Certain animals are produced only at certain seasons of the year, both in water and on the land, such, for instance, as scallops, snails, and leeches, in the spring, which also disappear at stated periods. Among fishes, the wolf-fish2789 and the trichias2790 bring forth twice in the year, as also do all kinds of rock-fish; the mullet and the chalcis2791 thrice in the year, the cyprinus2792 six times, the scorpæna2793 twice, and the sargus in spring and autumn. Among the flat-fish, the squatina brings forth twice a year, being the only2794 one that does so at the setting of the2795 Vergiliæ in autumn. Most fish spawn in the three months of April, May, and June. The salpa brings forth in the autumn, the sargus, the torpedo, and the squalus2796 about the time of the autumnal equinox. The soft fishes2797 bring forth in spring, the sæpia every month in the year; its eggs adhere together with a kind of black glutinous substance, in appearance like a bunch of grapes, and the male is very careful to go among them and breathe2798 upon them, as otherwise they would be barren. The polypi couple in winter, and produce eggs in the spring twisted in spiral clusters, in a similar manner to the tendrils of the vine; and so remarkably prolific are they, that when the animal is killed in a state of pregnancy, the cavities of the head are quite unable to contain the multitude2799 of eggs enclosed therein. They bring forth these eggs at the fiftieth day, but in consequence of the vast number of them, great multitudes perish. Cray-fish, and other sea-animals with a thinner crust, lay their eggs one upon the other, and then sit upon them. The female polypus sometimes sits upon its eggs, and at other times closes the entrance of its retreat by spreading out its feelers, interlaced like a net. The sæpia brings forth on dry land, among reeds or such sea-weed as it may find growing there, and hatches its eggs on the fifteenth day. The loligo produces its eggs out at sea, clustered together like those of the sæpia. The purple,2800 the murex, and other fishes of the same kind, bring forth in the spring. Sea-urchins have their eggs at full moon during the winter; sea-snails2801 also are produced during the winter season.