ALTERNATE PHASES IN FOLLICULINA. 85 



suggests a series of internal events that must be accomplished 

 before each phase must give place to the next. 



As is often the case in normal specimens the free swimming 

 phases in this imprisoned animal were in the daytime and the 

 sedentary phases in the night-time so that one might suppose 

 the phases to be dependent upon some concomitant of day and 

 night alternations, especially as the animal is deeply pigmented 

 both in its granules and also throughout its plasma, so that it 

 should be affected by light and heat; however, there were many 

 instances where the transitions from phase to phase seemed to 

 be quite independent of alternations of light and darkness. The 

 free swimming forms are very responsive to light and generally 

 positive and this favors their swarming out in the daytime. 

 However the dedifferentiation that precedes swarming may be 

 associated with metabolic changes that have but remote connec- 

 tion with diurnal changes. How far these internal factors may 

 be thought of along the lines suggested by E. J. Lund (8) remains 

 for future experimentation to discover. 



As in bursaria so in folliculina the nuclei remain apparently 

 unchanged during the transformations from phase to phase and 

 the transformations are those of the organs of external relation 

 feeding, muscular and ciliary movements and responsiveness. 



Regarding the closure of the tube as presenting problems to 

 be solved by the folliculina, it is difficult to see how an intelligent 

 animal could have solved them more satisfactorily with the 

 implements at hand: and were there a complex nerve system 

 present we might assume activities within it like those of a 

 higher animal, such as would lead to omission of the secretion 

 of a useless dwelling after some tactual appreciation of the 

 existence of one formerly secreted. 



Granting some internal sequences that lead to alternate forms 

 despite usual or unusual external conditions the most difficult 

 question is why the secretion of a dwelling was omitted when the 

 animal was held confined within the old dwelling. The omission 

 of this series of activities that normally takes place like a chain 

 of reflexes, leads to the appearance of a remarkable parsimony, 

 as if the presence of the old dwelling was a signal for the neglect 

 to construct a new one. 



