An C. M. Child 
oral and aboral ends lies at or near the equator on the outer sur- 
face, but changes from this position may occur. 
3. In some cases regulation goes no further, but usually one or 
more groups of tentacles appear at or near the line of union. The 
tentacle groups consist of varying numbers of tentacles—in my 
experiments from one to twelve—and show various degrees of 
approach to a perfect radial symmetry, the one extreme being a 
series of tentacles on each side of the line of BBR the other a 
perfectly radially symmetrical group. 
4. The localization of the groups along the line of union is very 
irregular and is apparently not determined by any factor directly 
connected with the original organization. Different degrees of 
injury to different parts of the circumference probably constitute 
a factor in their localization. 
5 In some cases the groups appear on the line of union and 
part of the tentacles arise from the original oral end of the plece, 
part from the aboral. Often oral-aboral tentacles appear, i. e., 
tentacles in the formation of which both oral and aboral ends take 
part. In other cases the whole group arises on the oral side of the 
line of union. Differences in the degree of injury of the two ends 
of the piece and perhaps also certain features of the original polar- 
ity, which persist, are probably factors in determining this locali- 
zation. 
6 The formation of the tentacle groups undoubtedly involves 
the establishment of a new polarity and in greater or less degree 
of a new radial symmetry. ‘The original polarity disappears to a 
greater or less extent in consequence of the union of the oral with 
the aboral end. ‘The establishment of the new polarities and 
symmetries 1s undoubtedly due to local factors in the regions where 
the groups appear. 
These cases of regulation, like axial heteromorphoses, are to be 
regarded as a breaking up or division of the original system in 
consequence of decrease or elimination of the original correlations: 
they are in short a kind of asexual reproduction, the differentiation 
of new systems being the result of the localization of regions of 
growth at various points in the tissues of the piece. 
