n my hand without injury. I then tried to
impregnate the eggs _mechanically_, and applied a drop of the
spermatic fluid to the egg at the moment of exclusion, and it
certainly seemed, in one instance, both to increase the size and
to alter the colour of the ova it was applied to; but I was not
able to produce the same effect so decidedly in any of my
subsequent attempts.

My observations, which were often repeated, induce me to believe
that the egg is impregnated at the moment of exclusion, and that
two males have (almost invariably) access to the female at the
same time; for I frequently remarked, that when a female came
among a number of males, they immediately pursued her: if she was
not ready for shedding her spawn, she made a precipitate retreat;
but if she was, she came boldly in among them, and was immediately
pressed closely by a male on each side, who when they had been in
that situation a short time, were superseded by other two, who
wedged themselves in between them and the female, who appeared to
treat all her lovers with the same kindness.

One difficulty is, that the spermatic fluid mixes very readily
with water; and I cannot imagine how its virtue is preserved, [14]
if (as I suppose must be the case) the egg is impregnated after
exclusion; but I also think it probable that the ventral fins of
the female serve to conduct this fluid to the place where it is
needed, and the chemical affinity between it and the egg may be
sufficient for impregnation.

P.S. July 27th. I tried to hatch some of the eggs I had
endeavoured to fecundate. The attempt was unsuccessful. I placed
the eggs, which I had put into some clean-washed gravel, in a
shallow vessel (open at the top, and with holes drilled through
the sides) in a small stream of water, but I found to my great
mortification on looking for them a day or two after that there
was not one left, but that in their stead were many aquatic
insects, which had no doubt feasted on them as long as they
lasted, and after this I was not able to meet with another shoal
of Minnows in the act of spawning.

The head of the Minnow in the spawning season is spotted over with
small white knobs, apparently osseous in their structure, which
make their appearance immediately before the fish begins to spawn,
and which disappear again as shortly after, and I think they are
intended as a protection to the head of the fish during the
spawning; as I remarked that they generally thrust