84 E. A. ANDREWS. 



swimming activity though not exposed to outside environment 

 but still within the same house in which the feeding phase had 

 lived, settled down and differentiated the feeding apparatus 

 again, though it skipped the usual making of a house. This 

 feeding stage not functioning as such again reverted to the 

 swimming phase which partly escaped from confinement but was 

 held tethered for such a long time that the next phase, the settling 

 and house building phase came into expression, with the result 

 that the anterior part of the animal made such a house as is 

 normally made by the entire animal while the posterior part of 

 the animal underwent cytolysis. 



This comparison may be put in tabular form: 



The Average Folliculina. The Imprisoned Folliculina. 



To use and resolve arms Many hours About twelve hours 



Only to resolve arms Several hours Two hours and more 



Free-swimming phase Two hours and more Two hours and more 



(inside house) 



To make sac One half hour 



To make tube Few hours 



To make lip Quarter to half hour All omitted 



To make whole house Four to eight hours 



To differentiate arms, etc One and three quarter to Six hours 



four and a half hours 



Again to use and resolve arms. . Many hours Nine hours or less 



Free-swimming phase Two hours and more Four hours (partly out 



of house) 



To make sac One half hour One hour 



To make tube Few hours Two hours 



To make lip Quarter to half hour Seventeen minutes 



(when stopped undone) 



It is then evident that long journeys through the water are not 

 necessary preliminaries to the settling down of the swimmer to 

 secrete and to differentiate. That the use of the feeding appa- 

 ratus is not necessary preliminary to the dedifferentiation of the 

 complex form into the simple; and that the anterior part of the 

 animal can act like a whole animal. In brief the external condi- 

 tions are not, for a time at all events, the necessary determining 

 factors in the transformations back and forth from sedentary 

 complex to migratory simple forms, or phases. Some internal 

 factors must be decisive in the alternation of forms. 



That time is spent in one phase and again in the next phase 



