314 MORGAN. [VOL. II. 



yet reduced sufficiently to give the piece the typical propor- 

 tions. Two other head-pieces of this same series are shown in 

 Fig. i, Z? 2 , /> 3 , that were drawn twenty-four hours after the 

 operation. It is even more evident in these (compare with 

 Fig. 2, A, for normal) than in the last that the peristome is too 

 broad for the length of the stentor. Even after another 

 twenty-four hours one of the pieces had still retained the same 

 form as shown in Fig. i, /? 4 . 



The posterior piece, C, fixes itself at once by the old foot, 

 and may soon elongate to its full length. In the course of 

 two or three hours a clear band appears extending somewhat 

 obliquely over the rounded end of the piece (Fig. i, C). Cilia 

 appear along the band. In a few more hours, the rate depend- 

 ing on the temperature, the ciliated band moves forward around 

 the anterior end of the piece, and in doing so bends around on 

 itself into the characteristic peristome. A new peristome- 

 field, or disk marked by delicate parallel lines, appears on the 

 inner side of the band even before it moves forward, and as 

 the band bends around to make the terminal peristome, the 

 new disk comes to lie in its central part. A depression, that 

 appears at the basal end of the band, forms the pharyngeal 

 funnel. The new peristome is smaller than that of the original 

 animal, and, as the figures show (Fig. i, C 1 , C' 2 , C s ), it is, in 

 some cases, even smaller than the reduced peristome on the 

 anterior piece. The foot-piece is also at first very long as com- 

 pared with the size of the new peristome ; and this condition 

 may remain for several days. 



These results demonstrate that, for some time after the new 

 organs have developed, the new stentors retain some of the 

 peculiarities of the part of body from which they have come. 

 When the pieces are contracted, or are swimming, these rela- 

 tions are scarcely evident and might easily escape detection. 



The transformation of an anterior piece into a new stentor 

 is much more strikingly seen when only a small part of the 

 anterior end is cut off. One set of observations on the same 

 individual is represented in Fig. 2. The stentor fully extended 

 is represented in Fig. 2, A. The anterior end had been cut 

 off, as shown in Fig. 2, A\ while the animal was contracted. 



