C. M. CHILD. 



In Fig. 8, a ring with three tentacle-bearing outgrowths and 

 one without tentacles is shown. The tentacles on two of the 

 three outgrowths are radially symmetrical, though unequal in 

 length and the discs show well-developed, radially arranged 

 mesenteries, but are without mouths. The third group is less 

 symmetrical and consists of only four tentacles. All the out- 

 growths appeared on one side, apparently the oral, of the line 

 of union. 



Fig. 9 shows a case, viewed obliquely from one side, in which 

 two groups of four tentacles each appeared, one on either side 

 of the line of union. This is the only case observed thus far in 

 which distinct groups appeared on different sides of the line of 

 union in a single ring and it is figured on that account. 



A case with seven distinct tentacle groups is shown in Fig. 10. 

 This is the largest number of distinct groups observed in any 

 single case. Apparently the formation of tentacle groups is in 

 general closely connected with the growth of new tissue in the 

 region of union, for they appear to be localized at points where 

 the areas of new tissue are greatest. At some points the two 

 cut edges may unite with scarcely any new tissue between them, 

 and in such regions tentacles are less likely to appear than in 

 regions with more new tissue. In the case shown in Fig. 10 an 

 unusually large amount of new tissue appeared as a more or less 

 continuous band about most of the circumference and in this 

 the tentacle groups developed. The area of the new tissue is 

 approximately indicated in the figure by the two dotted lines. 



And finally, Fig. II shows a case in which the symmetry of 

 the groups is mostly bilateral rather than radial. Here the cor- 

 responding parts of each group arise on opposite sides of the 

 line of union. I believe that groups of this kind appear when the 

 old organization is less injured and the old polarity less com- 

 pletely eliminated than in other cases. Although tentacles ap- 

 pear in such cases on the aboral as well as on the oral side of the 

 line of union, nevertheless the development of such rows of ten- 

 tacles is manifestly a less extreme change from the "normal" 

 arrangement with respect to the cut surface of the body wall 

 than the formation of distinct, radially symmetrical groups on 

 one side or the other of the line of union. It will be observed 



