the males of mammals: I presume that the bastard-wing in birds may be
safely considered as a digit in a rudimentary state: in very many
snakes one lobe of the lungs is rudimentary; in other snakes there are
rudiments of the pelvis and hind limbs. Some of the cases of
rudimentary organs are extremely curious; for instance, the presence of
teeth in foetal whales, which when grown up have not a tooth in their
heads; and the presence of teeth, which never cut through the gums, in
the upper jaws of our unborn calves. It has even been stated on good
authority that rudiments of teeth can be detected
in the beaks of certain embryonic birds. Nothing can be plainer than
that wings are formed for flight, yet in how many insects do we see
wings so reduced in size as to be utterly incapable of flight, and not
rarely lying under wing-cases, firmly soldered together!
The meaning of rudimentary organs is often quite unmistakeable: for
instance there are beetles of the same genus (and even of the same
species) resembling each other most closely in all respects, one of
which will have full-sized wings, and another mere rudiments of
membrane; and here it is impossible to doubt, that the rudiments
represent wings. Rudimentary organs sometimes retain their
potentiality, and are merely not developed: this seems to be the case
with the mamm of male mammals, for many instances are on record of
these organs having become well developed in full-grown males, and
having secreted milk. So again there are normally four developed and
two rudimentary teats in the udders of the genus Bos, but in our
domestic cows the two sometimes become developed and give milk. In
individual plants of the same species the petals sometimes occur as
mere rudiments, and sometimes in a well-developed state. In plants with
separated sexes, the male flowers often have a rudiment of a pistil;
and Kolreuter found that by crossing such male plants with an
hermaphrodite species, the rudiment of the pistil in the hybrid
offspring was much increased in size; and this shows that the rudiment
and the perfect pistil are essentially alike in nature.
An organ serving for two purposes, may become rudimentary or utterly
aborted for one, even the more important purpose; and remain perfectly
efficient for the other. Thus in plants, the office of the pistil is to
allow the pollen-tubes to reach the ovules protected in the ovarium at
its base. The pistil consists of a stigma
supported on the style; but in some Composit , the male florets, which
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