SECT. IL 



THE ACINETA. 



77 



particle mixed with water into vacuoles which they 

 make in the interior of the soft sarcode which fills the 

 bell, and there the particles undergo rotation till di- 

 gested and absorbed, and, if refuse remain, it is ejected 

 through a softer part in the outer layer of the bell. 



The stem that 

 fixes the animal 

 to a solid object 

 is a tubular con- 

 tinuation of its 

 outer membrane, 

 containing a high- 

 ly contractile fila- 

 ment ; and, as the 

 creature is ex- 

 tremely sensitive 

 to external impres- 

 sions, it folds up 

 the ciliated rim of 

 its bell, and its 

 stalk shrinks down 

 in a spiral on the 

 slightest alarm, but 

 the bell opens and 

 the stalk stretches 

 out again as soon 

 as the alarm is 

 over. WhenaYor- 

 ticella is repro- 

 duced by division, 



the bell separates longitudinally into two parts; one is 

 often smaller than the other, and separates from its 

 parent, swims about till it gets a stem, and fixes itself 

 to an object. When the two parts are of equal size, the 

 division extends to a greater or less distance down the 

 stalk, and as each of these become perfect bells, and do 



Fig. 108. Acineta. 



