244 THE EVOLUTION OF CONTINUITY 



VII. The Continuously Megazooidal Individual. — The 

 alternation here is sometimes as in VI ; but in certain 

 compound corals, such as Alcyonaria, some megazooids are 

 permanently arrested for special function and never become 

 sexual ; the phenomenon being very striking. 



VIII. The Radiate Individual. — The only alternation is 

 cellular, the Individual being one cellularly-continuous 

 organism. 



IX. The Discontinuous Segmental Individual. — In what 

 might be called a typical case, such as Aphis, the alter- 

 nation is generally similar to that in I, IV, and VI ; that 

 is, it is cellular, and also the alternation of a sexless with 

 a sexual cell-multiple. The discontinuity of the " neuter " 

 aphis would lead one to suppose that were life prolonged 

 enough, repeated " gemmation " would end in the produc- 

 tion of sexual elements. But the presumably permanent 

 arrest of the neuters makes these contrast strikingly with 

 the final sexual forms. The case of the honey-bee 

 is peculiar, for there are three classes of Bee-Individual. 

 In one of these, the sterile worker, there is no alternation 

 of any sort, because no sexual elements are produced. In 

 a second, the occasionally drone-producing worker, this 

 insect alternates with the sexual males formed from it. 

 In the drone itself there is cellular alternation. In the 

 third, the queen-bee Individual, the somatic cells of the 

 queen alternate with her true ova, and the somatic cells 

 of the drones she produces alternate with the drones' male 

 elements. 



X. The Continuously Segmental Individual. — Cellular 

 alternation alone is exhibited. It is true that certain 

 segments contain no sexual organs and alternate with those 

 that do, but owing to close continuity the segment cannot 

 as a rule be strictly delimited. In an organism like the 

 earthworm we might say there was segmental alternation. 



In the above sense it is therefore suggested that " alter- 

 nation of generations " is a phenomenon exhibited in some 

 form in all living Individuals ; and that it is truly the 

 alternation of intermediate cycle-stages with terminal 

 sexual forms as affected by varying intensifications of 

 Continuity. 



