ighest
authority. Mr. YARRELL in his "_History of British Fishes_," adverting
to the fact that ponds which had been previously converted into hardened
mud, are replenished with small fish in a very few days after the
commencement of each rainy season, offers this solution of the problem
as probably the true one: "The impregnated ova of the fish of one rainy
season, are left unhatched in the mud through the dry season, and from
their low state of organisation as ova, the vitality is preserved till
the recurrence, and contact of the rain and oxygen in the next wet
season, when vivification takes place from their joint influence."[1]

[Footnote 1: YARRELL, _History of British Fishes_, introd. vol. i. p.
xxvi.]

This hypothesis, however, appears to have been offered upon imperfect
data; for although some fish like the salmon scrape grooves in the sand
and place their spawn in inequalities and fissures; yet as a general
rule spawn is deposited not beneath but on the surface of the ground or
sand over which the water flows, the adhesive nature of each egg
supplying the means of attachment. But in the Ceylon tanks not only is
the surface of the soil dried to dust after the evaporation of the
water, but the earth itself, twelve or eighteen inches deep, is
converted into sun-burnt clay, in which, although the eggs of mollusca,
in their calcareous covering, are in some instances preserved, it would
appear to be as impossible for the ova of fish to be kept from
decomposition as for the fish themselves to sustain life. Besides,
moisture in such situations is only to be found at a depth to which
spawn could not be conveyed by the parent fish, by any means with which
we are yet acquainted.

But supposing it possible to carry the spawn sufficiently deep, and to
deposit it safely in the mud below, which is still damp, whence it could
be liberated on the return of the rains, a considerable interval would
still be necessary after the replenishing of the ponds with water to
admit of vivification and growth. But so far from this interval being
allowed to elapse, the rains have no sooner ceased than the fishing of
the natives commences, and those captured in wicker cages are mature and
full grown instead of being "small fish" or fry, as affirmed by Mr.
Yarrell.

Even admitting the soundness of his theory, and the probability that,
under favourable circumstances, the spawn in the tanks might be
preserved during the dry season so as to c