RUDIMEMTARY AND ABORTED ORGANS. 439 



RUDIMENTARY, ATROPHIED, AND ABORTED ORGANS. 



Organs or parts in this strange condition, bearing the 

 plain stamp of inutility, are extremely common, or even 

 general, throughout nature. It would be impossible to name 

 one of the higher animals in which some part or other is 

 not in a rudimentary condition. In the mammalia, for 

 instance, the males possess rudimentary mammae ; in snakes 

 one lobe of the lungs is rudimentary; in birds the "bastard- 

 wing " may safely be considered as a rudimentary digit, and 

 in some species the whole wing is so far rudimentary that 

 it cannot be used for flight. What can be more curious than 

 the presence of teeth in fcetal whales, which when grown up 

 have not a tooth in their heads ; or the teeth, which never 

 cut through the gums, in the upper jaws of unborn calves ? 



Rudimentary organs plainly declare their origin and mean- 

 ing in various ways. There are beetles belonging to closely 

 allied species, or even to the same identical species, which 

 have either full-sized and perfect wings, or mere rudiments 

 of membrane, which not rarely lie under wing-covers firmly 

 soldered together ; and in these cases it is impossible to 

 doubt that the rudiments represent wings. Rudimentary 

 organs sometimes retain their potentiality : this occasion- 

 ally occurs with the mammae of male mammals, which have 

 been known to become well developed and to secrete milk. 

 So again in the udders in the genus Bos, there are normally 

 four developed and two rudimentary teats ; but the latter in 

 our domestic cows sometimes become well developed and 

 yield milk. In regard to plants, the petals are sometimes 

 rudimentary, and sometimes well developed in the individ- 

 uals of the same species. In certain plants having separated 

 sexes, Kolreuter found that by crossing a species, in which 

 the male flowers included a rudiment of a pistil, with an 

 hermaphrodite 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 rudimen- 

 tary and perfect pistils are essentially alike in nature. An 

 animal may possess 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 



