No. 6.] PROPORTIONATE STRUCTURES IN STENTOK. 323 



other cases, in which the piece was small in comparison to the 

 size of the remaining part of the peristome, a new peristome 

 did not appear in one case until after thirty hours (Fig. 5, B 4 ) ; 

 in other cases a new peristome had not appeared at this time 

 (Fig. 5, 3 ). 



The complementary piece (C, Fig. 5) closed in, fixed itself, 

 and extended to its full length. In pieces in which the 



FIG. 5. A, stentor partially contracted, cut in two at a-a into a small piece, B, and a large 

 piece, C; B 1 , piece like B after seven hours ; B 2 , piece like B after twenty-seven hours; 

 3, B*, piece like B after twenty-nine hours ; C 1 , C 1 , piece like C after seven hours ; C 2 , 

 piece like C after twenty-nine hours ; O, C*, piece like C after fifty-one hours. 



remaining part of the peristome, that had united to make a 

 ring, was quite small a new ciliated band appeared in four 

 hours; in others, in six hours (Fig. 5, C 1 C 1 ) ; and in pieces with 

 a larger peristomial region, after twenty-four and even after 

 fifty-one hours (Fig. 5, C z ). It is interesting to note that in 

 these pieces the region from which in the normal individual 

 the peristomial band is formed has been more or. less com- 

 pletely removed, yet a new peristomial band may very quickly 



