t bore stripes of
perfectly characterised lemon-peel: with peas, several observers have seen
the colour of the seed-coats and even of the pod directly affected by the
pollen of a distinct variety; so it has been with the fruit of the apple,
which consists of the modified calyx and upper part of the flower-stalk.
These parts in ordinary cases are wholly formed by the mother-plant. We
here see the male element affecting and hybridising not that part which it
is properly adapted to affect, namely the ovule, but the partially
developed tissues of a distinct individual. We are thus brought half-way
towards a graft-hybrid, in which the cellular tissue of one form, instead
of its pollen, is believed to hybridise the tissues of a distinct form. I
formerly assigned reasons for rejecting the belief that the mother-plant is
affected through the intervention of the hybridised embryo; but even if
this view were admitted, the case would become one of graft-hybridism, for
the fertilised embryo and the mother-plant must be looked at as distinct
individuals.

With animals which do not breed until nearly mature, and of which all the
parts are then fully developed, it is hardly possible that the male element
should directly affect the female. But we have the analogous and perfectly
well-ascertained case of the male element of a distinct form, as with the
{366} quagga and Lord Morton's mare, affecting the ovarium of the female,
so that the ovules and offspring subsequently produced by her when
impregnated by other males are plainly affected and hybridised by the first
male.

_Development._--The fertilised germ reaches maturity by a vast number of
changes: these are either slight and slowly effected, as when the child
grows into the man, or are great and sudden, as with the metamorphoses of
most insects. Between these extremes we have, even within the same class,
every gradation: thus, as Sir J. Lubbock has shown,[886] there is an
Ephemerous insect which moults above twenty times, undergoing each time a
slight but decided change of structure; and these changes, as he further
remarks, probably reveal to us the normal stages of development which are
concealed and hurried through, or suppressed, in most other insects. In
ordinary metamorphoses, the parts and organs appear to become changed into
the corresponding parts in the next stage of development; but there is
another form of development, which has been called by Professor Owen
metagenesi