RUDIMENTARY ORGANS 406 



the lungs is rudimentary ; in other snakes there are 

 rudiments of the pelvis and hind limbs. Some of the 

 cases of rudimentary organs are extremely curious ; 

 for instance, the presence of teeth in fcetal whales, 

 which when grown up have not a tooth in their heads ; 

 and the presence of teeth, which never cut through the 

 gums, in the upper jaws of our unborn calves. It has 

 even been stated on good authority that rudiments of 

 teeth can be detected in the beaks of certain embryonic 

 birds. Nothing can be plainer than that wings are 

 formed for flight, yet in how many insects do we see 

 wings so reduced in size as to be utterly incapable of 

 flight, and not rarely lying under wing-cases, firmly 

 soldered together ! 



The meaning of rudimentary organs is often quite 

 unmistakable : for instance there are beetles of the 

 same genus (and even of the same species) resembling 

 each other most closely in all respects, one of which will 

 have full-sized wings, and another mere rudiments of 

 membrane ; and here it is impossible to doubt, that the 

 rudiments represent wings. Rudimentary organs some- 

 times retain their potentiality, and are merely not 

 developed : this seems to be the case with the mammas 

 of male mammals, for many instances are on record of 

 these organs having become well developed in full-grown 

 males, and having secreted milk. So again there are 

 normally four developed and two rudimentary teats in 

 the udders of the genus Bos, but in our domestic cows 

 the two sometimes become developed and give milk. 

 In plants of the same species the petals sometimes occur 

 as mere rudiments, and sometimes in a well-developed 

 state. In plants with separated sexes, the male flowers 

 often have a rudiment of a pistil ; and Kolreuter found 

 that by crossing such male plants with an hermaphro- 

 dite species, the rudiment of the pistil in the hybrid 

 offspring was much increased in size ; and this shows 

 that the rudiment and the perfect pistil are essentially 

 alike in nature. 



An organ serving for two purposes, may become rudi- 

 mentary or utterly aborted for one, even the more 



