Chap. XIV.] AND ABORTED ORGANS. 257 



important purpose, and remain perfectly efficient for 

 the otlier. Tims 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 ; l)ut in some Composit;p, the male florets, 

 which of course cannot be fecundated, have a rudimen- 

 tary 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 

 of 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, 

 unless we have reason to suppose that they were 

 formerly more highly developed, ought not to be con- 

 sidered as rudimentary. They may be in a nascent 

 condition, and in progress towards further development. 

 Rudimentary organs, on 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 con- 

 dition 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 have been partially 

 retained by the power of inheritance, and relate to a 

 former state of things. It is, however, often difficult to 

 distinguish between rudimentary and nascent organs ; 



