i6 



[VOL. II. 



days later (Fig. 2, P) the stalk was somewhat longer, and after 

 another four days (Fig. 2, /> 3 ) the form had not materially 

 changed. The development of the posterior piece of this same 

 individual is shown in Fig. 2, C 1 and C 2 . The piece is about 

 twice as long as the anterior piece, but its peristome is about 

 the same size. 



A similar operation was carried out on another individual ; 

 the results are shown in Fig. 3, A. A very small part of the 



B 



C 1 



FIG. 3. A, 1.7x4. Stentor fully extended ; A 1 , same contracted, cut in two at a-a ; B,C, 

 immediately after operation; B l , .5 x .21, five hours after operation ; B 2 , .5 x .24, three 

 days after operation; C 1 , posterior piece, 1.2 x .27, five hours after operation ; C 2 , same, 

 1.6 x .32, three days after operation. In Figs. 2 and 3 one individual used in each. In 

 Fig. i several individuals were used. 



anterior end was cut off (Fig. 3, A 1 }. It contained, however, 

 the entire peristome and disk (Fig. 3, B}. About thirty hours 

 after the operation the anterior piece appeared as shown in 



