258 RUDIMENTARY, ATROPHIED, [Chap. XIV. 



whether a part is capable of further development, in 

 which case alone it deserves to be called nascent. Or- 

 gans in this condition will always be somewhat rare; 

 for beings thus provided will commonly have been sup- 

 planted by their successors with the same organ in a 

 more perfect state, and consequently will have become 

 long ago extinct. The wing of the penguin is of high 

 service, acting as a fin; it may, therefore, represent the 

 nascent state of the wing: not that I believe this to be 

 the case; it is more probably a reduced organ, modi- 

 fied for a new function: the wing of the Apteryx, on the 

 other hand, is quite useless, and is truly rudimentary. 

 Owen considers the simple filamentary limbs of the Lepi- 

 dosiren as the "beginnings of organs which attain full 

 functional development in higher vertebrates; " but, ac- 

 cording to the view lately advocated by Dr. Giinther, 

 they are probably remnants, consisting of the persist- 

 ent axis of a fin, with the lateral rays or branches abort- 

 ed. The mammary glands of the Ornithorhynchus may 

 be considered, in comparison with the udders of a cow, 

 as in a nascent condition. The ovigerous frena of cer- 

 tain cirripedes, which have ceased to give attachment 

 to the ova and are feebly developed, are nascent bran- 

 chiae. 



Eudimentary organs in the individuals of the same 

 species are very liable to vary in the degree of their 

 development and in other respects. In closely allied 

 species, also, the extent to which the same organ has 

 been reduced occasionally differs much. This latter fact 

 is well exemplified in the state of the wings of female 

 moths belonging to the same family. Eudimentary or- 

 gans may be utterly aborted; and this implies, that in 

 certain animals or plants, parts are entirely absent which 



