CHAP. 75.—FISHES WHICH ARE BOTH OVIPAROUS AND VIVIPAROUS.
The torpedo is known to have as many as eighty young
ones. It produces within itself[1] very soft eggs, which it then
transfers to another place in the uterus, and from that part
ejects them. The same is the case with all those fish to which
we have given the name of cartilaginous; hence it is, that
these alone of all the fishes are at once viviparous and oviparous.
The male silurus[2] is the only fish among them all that watches
the eggs after they are brought forth, often for as long a period
as fifty days, that they may not be devoured by other fish.
The females of other kinds bring forth their eggs in the course
of three days, if the male has only touched them.
1. All the chondropterygian fishes, Cuvier says, have, in addition to their
ovaries, real oviducts, which the ordinary fishes have not; the lower part
of which, being detached, acts as the uterus, into which the eggs descend
when they have gained their proper size: and it is here that the young
ones burst forth from the egg, when the parent animal is viviparous.
2. Aristotle, Hist. Anim. B. vi. c. 13, says the same of the glanis, or
silurus.