ASEXUAL CYCLE OF PLAXARIA VELATA. 189 



TABLE III. 



No Encystment. Encystment. 



a go 10 



b 60 40 



Series 20, April ij, ign, Ten worms from same stock, of 

 same size and in same condition as Series 19. Heads removed 

 and body cut into four equal pieces, a, 6, c, d, a being the most 

 anterior. Table IV. gives the results. 



TABLE IV. 



No Encystment. Encystment. 



a 90 10 



b 80 20 



c 30 70 



d 20 80 



Series 27, April 77, ign. Ten worms like those of Series 19 

 and 20 in size and condition. Heads removed and body cut into 

 eight equal pieces, a-h, a being the most anterior. The results 

 are given in Table V. 



TABLE V. 



No Encystment. Encystment. 



a 20 70 



b 10 90 



c 100 



d 100 



e 100 



/ 100 



g 100 



h 100 



It is evident from these three series and abundantly confirmed 

 by numerous others, first, that the frequency of encystment of 

 pieces increases from the anterior to the posterior end of the body 

 and second, that the frequency of encystment increases as the 

 size of the piece decreases. In all these series the greater fre- 

 quency of encystment in more posterior pieces is evident in 

 greater or less degree. In Series 19 where the pieces represent 

 halves of the body the percentages of encystments are small, 

 in Series 20, composed of | pieces, they are larger except in the 



