THE BOTTLE ANIMALCULE, FOLLICULINA. 



279 



built out from the old rmuth of the tube, and this added extension 

 has but imperfect spiral ridges. 



Another aggregate of only nineteen individuals is shown in 

 Fig. 4, as seen from the side. This was formed in the same way 

 but on the edge of another floating cover glass. The continuous 

 line they are attached to is the continuous film they secreted and 

 which was pulled off from the glass with all the cases in making 

 this preparation. Though the thickness of the cover glass was 

 but 150 IJL. some sacs are placed back of one another on the end of 

 the glass and so are partly hid by those in front, in the sketch. 



Others, however, as 6 and 8, are not fast to the glass but are 

 built up on top of other cases. Here again the cases are densely 

 crowded together with very little space not occupied and the 

 tubes radiate outward from the group as a whole, though in this 

 case the group has the form of a linear aggregate. 



In this preparation the animals are better preserved; No. 9 is 

 about to expand outside of its tube; No. 13 is much elongated 

 while in No. 10 is one caught in the act of escaping from its 

 tube to swim away as the motile form without the characteristic 

 long arms of the tube dwellers. 



FIG. 5. Section, 6 ju thick, of a group formed on surface of water, to show that 

 not all are on one plane but some are piled on top of others. All are held together 

 by or attached to, a common secretion. Camera lucida X 66. 



That the cases of Folliculina are not only made in contact 

 with the foreign substance but also in contact with other tubes 

 and above the general level is shown in actual sections of such 

 aggregates. Thus in the 6 /JL section, Fig. 5, several cases are 

 seen piled up on top of others that rest on the. common basis 

 which was a pellicle formed by the Folliculina on the surface of 

 the water. Between some of these cases not in close contact 



