Origin of Species Variorum

Comparison with 1872

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 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 Compositæ, the male florets, which of course cannot be fecundated, have a pistil, which is in a rudimentary state, 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 of the surrounding 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, unless 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 in the other hand, are either quite useless, such as teeth which never cut through the gums, or almost useless, such as the wings of an ostrich, which serve merely as sails. ↑ As organs in this condition would formerly, when still less developed, ... have been of even less use than at present, they cannot formerly have been produced through variation and natural selection, which .. acts solely by the preservation of useful modifications. ↑ They cannot, therefore, under their present condition, have been formed by natural selection, which acts solely by the preservation of useful modifications; they have been retained, as we shall see, by inheritance, and relate to a former condition of their possessor. It is, however, often difficult to distinguish between rudimentary and nascent organs; for we can judge only by analogy whether a part is capable of further development, in which case alone it deserves to be called nascent. Organs in this

"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 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 within the ovarium. .. .. .. The pistil consists of a stigma supported on a style; but in some Compositæ, 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 with hairs, in the usual manner, for brushing the pollen out of the surrounding and conjoined anthers. Again, an organ may become rudimentary for its proper purpose, and be used for a distinct object: in certain fish the swimbladder seems to be nearly rudimentary for its proper function of giving buoyancy, but has become converted into a nascent breathing organ or lung. Other similar instances could be given.

Organs, however little developed, if of use, should not be considered as rudimentary: they may be called nascent, and may hereafter be developed by natural selection to any further extent. Rudimentary organs, on the other hand, are essentially useless, as teeth which never cut through the gums. ↑ As they would be of even less use, when in a still less developed condition, they cannot have been formed through variation and natural selection, which latter acts solely by the preservation of useful modifications. They relate to a former state of things, and have been partially retained by the power of inheritance. It is difficult to know what organs are nascent; looking to the future, we can- not of course tell how any part will be developed, and whether it is now in a nascent condition; looking to the past, creatures with an organ in this