The writer tried whether or not by tying a ligature around the middle of a piece of an Actinian this polarity could be suppressed; but the experiments did not succeed, inasmuch as the cells compressed by the ligature died, and were liquefied through bacterial action so that the pieces in front and behind the ligature fell apart. It is therefore impossible to decide whether or not a current or a flow of substances in a certain direction through these elements is responsible for this polarity, though this may be possible. The writer found, however, that one condition is necessary for the growth and regeneration of tentacles which also plays a rôle in the corresponding phenomena in plants, namely turgidity. The tentacles of _Cerianthus_ are hollow cylinders closed at the tip, and by liquid being pressed into them they can be stretched and appear turgid. If, however, an incision is made in the body, the tentacles above the incision can no longer be stretched out. In one experiment the oral disk of a _Cerianthus_ was cut off; very soon new tentacles began to grow at the top, and after having reached a certain size, an incision was made in the animal. The tentacles above the incision collapsed in consequence and ceased to grow, while growth of the others continued. On the lower edge of the incision new tentacles began to grow. [Illustration: FIG. 27] It seems also possible that Morgan’s well-known experiment on regeneration in _Planaria_ can be explained by a flow of substances. He[159] found that if a piece _a c d b_ be cut out of a fresh-water Planarian at right angles to the longitudinal axis (Fig. 27), at the front end a new normal head, at the back end a new tail, will be regenerated (Fig. 28); but that if a piece _a c d b_ be cut from a Planarian obliquely (Fig. 29) instead of at right angles to the longitudinal axis a tiny head is formed at the foremost corner of the piece _a_ and a tiny tail at the hindmost corner _b_ (Fig. 30). Why is it that in the oblique piece the head is formed in the corner and not all along the cut surface as is the case when the cut is made at right angles to the longitudinal axis? The writer is inclined to believe that the right answer to this question has been given by Bardeen.[160] This author has pointed out the apparent rôle that the circulatory (or so-called digestive) canals in Planarians play in the localization of the phenomena of regeneration, inasmuch as the new head always forms symmetrically at the opening of the circulatory vessel or branch which is situated as much as possible at the foremost end of the regenerating piece of worm. He assumes that through muscular action the liquids of the body are forced to stream toward this end, and that this fact has some connection with the formation of a new head. There can be no doubt that the facts here mentioned agree with Bardeen’s suggestion. The oblique pieces in Morgan’s experiments which at first have the heads and