ALTERNATE PHASES IN FOLLICULINA. 



swimmer vainly tried to force itself out of the tube end, but did 

 not succeed in boring its way out with the narrower tip of the 

 body and all possible efforts (Fig. 3). After two hours and a 

 half of this free-swimming life inside of the case, the free-swimmer 

 settled down to the bottom of the case and became attached 

 there by its foot end again, thus settling down as it naturally 

 would have done after the same interval of time had it, as normal, 



FIG. i. FIG. 2. 



FIG. i. Folliculina trapped inside closed case, ded iff e rent ia ting its lobes at 7.50 

 A.M., August 29, 1914.' 



FIG. 2. Same at 9.50 with lobes gone and free-swimming form completed. 



swum free through the water to some distant point of contact 

 and selected a new solid surface to become attached to, far from 

 its old dwelling. 



From 12:50 onwards the newly attached larva at the bottom 

 of the case was seen to be reconstructing its lobes (Fig. 4) and 

 this process was completed at 10 P.M. In this process of making 

 lobes (Fig. 4) the usual series of phenomena took place just as is 

 the rule after a free life and formation of a new tube; but here 

 the old tube was used to dwell in and no new tube was formed. 



1 Explanation of Illustrations. All sketches outlined with camera lucida, Zeiss, 

 4, D, that is enlarged about 700 diameters and then reduced to one third in 

 diameter. 



All sketches are successive views of one individual Follicitlina. 



