on the average, however
many or however few the offspring to start with, just enough attain
maturity in the long run to replace their parents in the next
generation. Were it otherwise, the sea would soon become one solid mass
of herring, cod, and mackerel.

These cat-fish, however, are not the only good fathers that carry their
young (like woodcock) in their own mouths. A freshwater species of the
Sea of Galilee, _Chromis Andreae_ by name (dedicated by science to the
memory of that fisherman apostle, St. Andrew, who must often have
netted them), has the same habit of hatching out its young in its own
gullet: and here again it is the male fish upon whom this apparently
maternal duty devolves, just as it is the male cassowary that sits upon
the eggs of his unnatural mate, and the male emu that tends the nest,
while the hen bird looks on superciliously and contents herself with
exercising a general friendly supervision of the nursery department. I
may add parenthetically that in most fish families the eggs are
fertilised after they have been laid, instead of before, which no doubt
accounts for the seeming anomaly.

Still, good mothers too may be found among fish, though far from
frequently. One of the Guiana catfishes, known as Aspredo, very much
resembles her countrywoman the Surinam toad in her nursery
arrangements. Of course you know the Surinam toad--whom not to know
argues yourself unknown--that curious creature that carries her eggs in
little pits on her back, where the young hatch out and pass through
their tadpole stage in a slimy fluid, emerging at last from the cells
of this living honeycomb only when they have attained the full
amphibian honours of four-legged maturity. Well, Aspredo among cat-fish
manages her brood in much the same fashion; only she carries her eggs
beneath her body instead of on her back like her amphibious rival. When
spawning time approaches, and Aspredo's fancy lightly turns to thoughts
of love, the lower side of her trunk begins to assume, by anticipation,
a soft and spongy texture, honeycombed with pits, between which are
arranged little spiky protuberances. After laying her eggs, the mother
lies flat upon them on the river bottom, and presses them into the
spongy skin, where they remain safely attached until they hatch out and
begin to manage for themselves in life. It is curious that the only two
creatures on earth which have hit out independently this original mode
of providing for