THE BOTTLE ANIMALCULE, FOLLICULINA. 



271 



form was begun with the making of cases which were completed 

 in from four to eight hours; in the evening one to several hours, 

 often, were taken to perfect the organization of the sessile form 

 in its new case. 



Within the twenty-four hours the entire cycle from sessile to 

 new sessile form was completed, and in extreme cases, only six 

 hours were necessary. 



FIG. 2. Sketch of motile form emerging from tube. Four successive stages of 

 one individual in row from left to right with same individual above swimming 

 free and later, below, gliding over surface of leaf. 



In nature then it is probable that the Folliculina on leaves of 

 Elodea give off swarms of motile forms that find the new upper 

 leaves, as well as floating leaves and objects in the deep waters 

 also as shown in the above experiments, and quickly settle 

 down to remain in new tubes till these leaves in turn become 

 unfavorable from accumulations of dirt and from shading by 

 overhanging leaves. Then there is new migration upward and 

 so on as long as food, temperature and other conditions allow. 



