The Descent of Man

esemble the females, and acquire their distinctive
masculine characters only at a later moult.
Strictly analogous cases occur at the successive
moults of certain male crustaceans.
We have as yet considered the transference of
characters, relatively to their period of development,
only in species in a natural state; we
will now turn to domesticated animals, and
first touch on monstrosities and diseases. The
presence of supernumerary digits, and the absence
of certain phalanges, must be determined
at an early embryonic period—the tendency to
profuse bleeding is at least congenital, as is
probably colour-blindness— yet these peculiarities,
and other similar ones, are often limited
in their transmission to one sex; so that the rule
that characters, developed at an early period,
tend to be transmitted to both sexes, here wholly
fails. But this rule, as before remarked, does
not appear to be nearly so general as the converse
one, namely, that characters which ap-