IQS BUDIMENTAEY, ATROPHIED, 



rudimentary that it cannot be used for fliglit. Wliat can 

 be more curious thau the presence of teeth in foetal 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? 



Eudimentary organs plainly declare their origin and 

 meanins: in various wavs. There are beetles belonsrins: to 

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

 vv'hich have either full- sized and perfect wings, or mere 

 rudiments of membi-ane, which not rarelv lie under wincr- 

 covers firmly soldered together; and in these cases it is im- 

 possible to doubt, that the rudiments represent wings. 

 Eudimentary organs sometimes retain their potentiality: 

 this occasionally occurs with the mammte 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 be- 

 come well developed and yield milk. In regard to plants, 

 the petals are sometimes rudimentary, and sometimes well 

 developed in the individuals of the same species. In cer- 

 tain 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 rudimentary and perfect pistils are 

 essentially alike in nature. An animal may possess vari- 

 ous 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 full-formed. 

 This animal never lives in the water. Yet if we open a 

 gravid female, we find tadpoles inside her with exquisitely 

 feathered gills; and when placed in water they swim about 

 like the tadpoles of the water-newt. Obviously this aquatic 

 organization has no reference to the future life of the 

 animal; nor has it any adaptation to its embiwonic con- 

 dition; it has solely reference to ancestral adaptations, it 

 repeats a phase in the development of its progenitors." 



