49. Moreover, he says that all the molluscous fish, and the shell-fish, and the cartilaginous fish, and all insects, spend a long time in copulation; but that the dolphin and some other fish copulate lying alongside the female. And he says that the dolphins are very slow, but fish in general very quick. Again he says that the lion has very solid bones, and that if they are struck, fire comes from them as from flint stones. And that the dolphin has bones, but no spine; but that cartilaginous fish have both gristle and spine. And of animals he says that some are terrestrial and some aquatic; and that some even live in the fire; and that there are some, which he calls ephemera, which live only one day: and that there are some which are amphibious, such as the river-horse, and the crocodile, and the otter. And that all animals in general have two forefeet, but that the crab has four; and that all the animals which have blood are either without feet at all, or are bipeds, or quadrupeds; and that all the animals which have more than four feet are destitute of blood: on which account every animal which moves, moves by what he calls four tokens,—man by two hands and two feet, a bird by two feet and two wings, an eel and a conger by two fins and two joints. Moreover, some animals have hands, as a man has, and some appear to have hands, as a monkey does; for there is no brute beast which can really give and take, and it is for those things that hands are given to men as instruments. Again, some animals have limbs, as a man, an ox, an ass; and some have no limbs, as a serpent, an oyster, the pulmo marinus. There are also many animals which are not always visible, such as those which hide in holes; and those which do not hide in holes are still not always visible, as swallows and cranes.