CONCLUSIONS AND SUGGESTIONS 197 



illustrated by a comparison of certain corals with tlie 

 plants. Wood- Jones' has recently found from a study 

 of living animals under natural conditions that in the 

 staghorn corals there is a radially symmetrical, apical 

 zooid at the tip of the stem which gives rise by budding 

 to the bilaterally symmetrical, lateral zooids, while 

 these do not reproduce as long as the apical zooid is 

 present and active. At a certain distance from the 

 apical zooid one of the bilaterally symmetrical zooids 

 may become radially symmetrical and begin to reproduce 

 new zooids and so become the apical zooid of a branch. 

 If the apical stem-region with the apical zooid is removed, 

 several branches may arise by the transformation of 

 bilateral into radial, reproducing zooids. Moreover, 

 the apical zooid of stem and branches remains young 

 indefinitely, while the lateral zooids which do not 

 reproduce undergo senescence and die. In other corals 

 various degrees of composite individuation are found 

 to exist. The relation of the dominant apical zooid 

 to other parts in the staghorn corals is very evidently 

 essentially the same as that between the growing tip 

 and other parts in plants, and it is impossible to doubt 

 that the same fundamental principle underlies and 

 determines the relation, not only in these two cases, 

 but in organisms in general. 



GAMETIC REPRODUCTION 



Sexual or gametic reproduction, with rare exceptions 

 the only reproductive process giving rise to whole new 

 organisms among the higher animals, is commonly 



^ F. Wood-Jones, Coral and Atolls, London, 191 2, chaps, viii, ix. 



