Factors of Form Regulation in Harenactis Attenuata 489 



transparency and delicacy, but there is no sharp boundary between 

 it and the old and the differences of the earlier stages soon dis- 

 appear, so that in these cases also it is impossible to determine 

 exactly to what extent localized growth occurs. The foot-region 

 does not differ from other parts of the body-wall in its gross ana- 

 tomical characteristics, therefore the only certain proof of the 

 restitution of the foot-region is attachment. 



Localized growth of new tissue can be greatly increased by 

 repeated operation, i.e., the growth-reaction after each operation 

 is much the same. It is possible in this manner to alter the shape 

 of the body to a very considerable degree. Figures 19 and 20 



19 20 



show the usual method of closure of a lateral transverse wound 

 not involving the oesophagus and not renewed after healing has 

 occurred the first time. The shaded region in the figures indicates 

 approximately the extent of the new tissue. In Figs. 21 and 22 

 two cases are shown in which the lateral cut was repeated a num- 

 ber of times, in each case after the preceding wound had healed. 

 Each healing involved more or less localized growth in the region 

 of the wound, and deformation of the body was the result. The 

 two figures show different processes of deformation depending 

 on the character of the wound. In Fig. 21 the wound was deep 



