TRANSFORMING AND REGENERATING ORGANS 631 



FIG. 153 



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 polyp they remain together. Very 

 soon all the tentacles begin to fuse 

 into a homogeneous mass. This 

 process of fusing begins usually at 

 the peripheral end of the 

 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) 

 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 



FIG. K4 



