ALTERNATE PHASES IN FOLLICULINA. 



E. A. ANDREWS. 



As long ago as 1858 it was independently affirmed by Wright 

 (7) and by Claparede and Lachmann (6) that the sedentary 

 marine infusorian once known as Freia, but called now by the 

 more prosaic term, the bottle animalcule, Folliculina, could 

 reduce itself to a more simple larva-like form and then swim free, 

 subsequently to make for itself a new dwelling in which to 

 differentiate again into the perfect form. 



So great was the difference in structure that the free swimming 

 form was regarded by Daday (3) as a new genus to be placed in 

 a family quite different from the family of Stentors in which the 

 adult sedentary Folliculina belongs. 



Even as late as 1916 Sahrlage (4) after much study of Follicu- 

 lina denies the reality of any process of alternation of differen- 

 tiated and dedifferentiated phases in Folliculina. He also denies 

 the credibility of the evidence that Folliculina is found in fresh 

 waters as well as in the sea. 



In both these negations he is shown to be wrong by Penard 

 (5) who studied fresh water Folliculinas and describes the trans- 

 formations from one phase to the other back and forth. 



However, both these authors, overlooked the fact that in 

 1914 (i, 2) the same alternation of sedentary and free swimming 

 phases early claimed for Folliculina in Europe had been found in 

 American waters. 



The present paper will serve to reaffirm the reality of this 

 alternation in Folliculina and to emphasize its fundamental 

 nature. 



Folliculina being the most specialized of the highly complex 

 Stentors presents in its anatomy an unusually high grade of 

 complexity, while its ability to fabricate a complex dwelling by 

 secretion is the acme of accomplishment among the ciliated 

 protozoa. 



Under the conditions elsewhere described (i, 2) Folliculina 



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