VORTICELLA. 123 



fissure will soon be perceived two bells will be 

 formed, and in time one will twist itself off, and, 

 swimming freely about for a period, at last fix 

 itself, and form a stalk. One extraordinary cir- 

 cumstance has been witnessed by those who 

 have watched minutely that the lower portion 

 of what may be called the new being, and which 

 was attached to the stalk, now becomes the 

 mouth, and is surrounded with cilia, whilst the 

 upper part closes and produces the stalk. I 

 have frequently observed a circle of cilia in ac- 

 tive motion on the lower part of the newly- 

 formed bell, even before it had left its parent, 

 but have never been so fortunate as to observe 

 what follows. When this newly-formed creature is 

 swimming about, it might be, and has been, taken 



