Chapter XII.

1. The oviparous fish have a divided uterus placed on the lower part of the body, as I observed before. All that have scales are viviparous, as the labrax, cestreus, cephalus, etelis,[204] and those called white fish, and all smooth fish except the eel. Their ova resemble sand. This appearance is owing to their uterus being quite full of ova, so that small fish appear to have only two ova; for the small size and thinness of the uterus renders it invisible in these creatures. I have before treated of the sexual intercourse of fish. The sexes are distinct in almost all fish, though there is some doubt about the erythrinus[205] and the channa, for all these are found to be pregnant.

2. Ova are found in those fish which have sexual intercourse, though they possess them without intercourse. This is observable in some kinds of river fish; for the phoxini[206] appear to be pregnant as soon as they are born, and when they are quite small. They emit the ova in a stream; and, as I observed before, the males devour great numbers of them, and others perish in the water. Those are preserved which they deposit in their appropriate situations. For, if all were preserved, the numbers that would be found would be immense. Not all those that are preserved are fertile, but only those on which the seminal fluid of the male has been sprinkled. When the female produces her ova, the male follows, and scatters his semen upon them. Young fish are produced from those ova which are thus sprinkled. The remainder turn out as chance may direct.

3. The same thing also occurs in the malacia; for the male sepia sprinkles the ova of the female as they are deposited; and it is reasonable to suppose that the other malacia do the same, although it has only been observed in the sepia. They produce their ova near the land, the cobii deposit them upon stones, and that which they produce is flat and sand-like. The rest do the same, for the parts near the land are warmer, and provision is more abundant, and there is better protection for their young against larger fish, for which cause very great numbers deposit their ova near the river Thermodon, in the Pontus, for the place is sheltered and warm, and the water is sweet.

4. The majority of viviparous fish reproduce once in a-year, except the small phycides,[207] which reproduce twice a-year. The male phyces differs from the female, being darker-coloured and having larger scales. All other fish produce from seed, and emit ova; but that which is called the belone, at the season of reproduction bursts asunder, and in this way the ova escape; for this fish has a division beneath the stomach and bowels, like the serpents called typhlinæ.[208] When it has produced its ova, it survives, and the wound heals up again.

5. The development of the ovum is alike, both in those that are internally and those that are externally oviparous. For it takes place at the extremity of the ovum, and it is enclosed in a membrane. The eyes are the first part that is conspicuous; they are large and spherical; so that it is plain that they are mistaken who say that the mode of development resembles that of vermiform creatures, for in them the order is different, and the lower parts are formed first, and afterwards the head and eyes. When the ovum is taken away, they assume a circular form, and for some time continue to grow without taking in any food, by absorbing the moisture of the ovum. They afterwards derive their nutriment, as long as they continue growing, from the water of the river.

6. When the Pontus is cleansed, something is floated out into the Hellespont which is called fucus. It is of a yellow colour. Some say that it is naturally a plant. This takes place at the beginning of summer. The oysters and small fish which live in these places feed upon this fucus; and some maritime persons say that they obtain their purple from this plant.