Page - 491 - in The Origin of Species

RUDIMENTARY ORGANS 491 flowers included a rudiment of a pistil, with an hermaphro- dite species, having of course a well-developed pistil, the rudiment in the hybrid offspring was much increased in size; and this clearly shows that the rudimentary and perfect pistils are essentially alike in nature. An animal may pos- sess various parts in a perfect state, and yet they may in one sense be rudimentary, for they are useless: thus the tadpole of the common Salamander or Water-newt, as Mr. G. H. Lewes remarks, "has gills, and passes its existence in the "water; but the Salamandra atra, which lives high up among "the mountains, brings forth its young full-formed. This "animal never lives in the water. Yet if we open a gravid "female, we find tadpoles inside her with exquisitely feath- "ered gills; and when placed in water they swim about like "the tadpoles of the water-newt. Obviously this aquatic "organisation has no reference to the future life of the "animal, nor has it any adaptation to its embryonic condition ; "it has solely reference to ancestral adaptations, it repeats "a phase in the development of its progenitors." An organ, serving for two purposes, may become rudimen- tary 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 within the ovarium. The pistil consists of a stigma supported on a style; but in some Compositae, the male florets, which of course cannot be fecundated, have a rudimentary pistil, for it is not crowned with a stigma; but the style remains well developed and is clothed in the usual manner with hairs, which serve to brush the pollen out o£ the surrounding and conjoined anthers. Again, an organ may become rudimentary for its proper purpose, and be used for a distinct one: in certain fishes the swim-bladder seems to be rudimentary for its proper function of giving buoyancy, but has become converted into a nascent breathing organ or lung. Many similar instances could be given. Useful organs, however little they may be developed, un- less we have reason to suppose that they were formerly more highly developed, ought not to be considered as rudimentary. They may be in a nascent condition, and in progress towards further development. Rudimentary organs, on the other hand.