148 INDIVIDUALITY IN ORGANISMS 



unite smoothly, and from this new tissue all gradations 

 from single tentacles, through groups of tentacles of 

 various sorts up to complete small anemones (Figs. 

 81-83) arise. 



The various tentacle groups in Figs. 81 and 82 and 

 the individual in Fig. 83 are made up of cells which are 

 descended from both apical and basal ends of the piece 

 and a more or less definite new individuation occurs 

 in these cells. There can be little doubt that in these 

 cases the origin of these various degrees of individuation 

 is associated with the growth of new tissue at the line of 

 union between the cut surfaces. The metabolic rate in 

 this tissue is higher than in the other regions of the piece, 

 and if it is enough higher the new tissue becomes inde- 

 pendent and produces a new apical region, or some part 

 of it, according to conditions. Wherever, about the 

 circumference, growth of new tissue is most rapid and 

 extensive, there the new individual is most likely to arise. 

 Often it is possible to determine beforehand the region 

 of the circumference where such tentacle groups or 

 individuals shall arise, by making the outline of one or 

 both cut surfaces irregular at some point or making a 

 number of small cuts near together in them. In such 

 'regions there is more growth of new tissue and a new 

 gradient and new individual are more likely to arise. 



As regards the minor axes, it is of great interest to 

 note the wide range of variations which occurs. Many 

 bilaterally as well as radially symmetrical and asym- 

 metrical forms appear among the tentacle-groups, and 

 it is evident that the symmetry of the groups is in many 

 cases related to the line of union and not to any pre- 

 existing symmetry of the parent animal. In these rings 



