TRANSFORMING AND REGENERATING ORGANS 631 
material of the stem begins with a shortening and folding 
together of the tentacles (polyp 1 in Fig. 153). This 
process is at the beginning the same as that which occurs 
upon any stimulation of the polyp and especially in the act 
of taking up food. But while in the 
latter case the tentacles unfold again, 
in the case of the transformation of 
the polyptheyremaintogether. Very 
soon all the tentacles begin to fuse 
into a homogeneous mass. This 
process of fusing begins usually at 
the peripheral end of the 
sa polyp (polyp 2, Fig. 153). 
A little later all the ten- 
tacles form an undifferen- 
tiated mass of protoplasm 
(see polyp 1, Fig. 154). ¥ 
In the next stage (2, Fig. 154) the 
2 original differentiation of the crown of 
the polyp into tentacles can no longer 
be recognized. 
At this stage the transformed shape- 
less mass of the polyp begins to flow 
back into the stem (1, Fig.155). A little later only 
a fraction of the original protoplasm of the polyp is 
left in the periderm, the rest having crept back into 
the stem (2, Fig.155). In polyps 3, 2, and 1 (Fig. 152) 
FIG. we see the further stages of this process of the polyp 
material flowing back into the stem. 
The transformation of polyps and their creeping into the 
stem occurs probably in a similar way in an Antennularia 
which is put into the water horizontally. The main difference 
between an Antennularia and a Campanularia is that in the 
latter this transformation is produced by the polyp coming 
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