i8o 



E. H. HARPER. 



cately adjusted. Cases occurred in which the prostomium was 

 regenerated, but the side of the head or lobe was not normally 

 restored, at least within the period of observation (cf. Fig. 13, of 

 a sexual individual). 



The general conclusion is that certain parts which may be 

 mutilated without exposing cut surfaces of internal organs which 

 are of importance as internal factors in proliferation are less likely 

 to be regenerated, since, when the proliferating tendency is slight, 

 the ectoderm closes over the wound and checks proliferation. 



I a. 



i i,. 



I c. 



2 a. 



26. 



4 a. 



5*- 



