202 THE THEORY OF EVOLUTION 



absorbed and changed into the staff-like attachments. 1 

 We have thus also in the individual development 

 strong evidence of the probability of the evolution 

 of this genus from the original stock. 



By the above our concluding principle is also 

 established, viz. that the adaptive phenomena in the 

 Ant guests and Termite guests provide an abundance 

 of evidence of the generic historical evolution of 

 new species, genera, and even families in the animal 

 kingdom i.e. their evolution from the original stocks. 



3. Suggestive points in the Embryogeny of the present 



organisms. 



(1) Premises and extent of the embryological 

 evidence. 



We have seen that even to-day causes are active 

 which can lead to the most multifarious transformations 

 of animals and plants. Thereby is clearly shown that 

 the germ cells of the altered forms are also influenced. 

 We will elucidate this by a simple example. If a plant 

 be transplanted from a valley, its usual habitat, to 

 an elevation of considerable height, there arise various 

 adaptive characters : the plant produces, for instance, 

 hairs as a protection from cold, its leaves become very 

 rich in chlorophyll (intensely green) in order to assimilate 

 more vigorously during the shorter period of vegetative 

 activity ; thereby the whole habit of the plant can be 



1 See Wasmann : Die ThorakalanMnge der Termitoxeniidce ( Verh. 

 der Deutschen Zoologischen Gesellschaft, 1903). 



