Grafting of Tnhulana 353 



the reverse direction on the proximal piece (Fig. 24). This 

 brought the distal tentacles into a position which was shghtly dif- 

 ferent from their normal one. The space in front of them, i. e., 

 between them and the end was greater than before. In a large 

 number of experiments the pieces united, the tentacles completed 

 themselves, and the normal hydranth emerged. In about 10 

 per cent of the grafts, a most interesting result was observed. The 

 original distal tentacle ridges remained as distinct bands, while 

 in front of them at the cut surface, a new row of distal tentacles and 

 hypostome developed, the hydranth finally emerged with the 

 stripes running from the base of the new distal tentacles to the 

 proximal ones (Fig. 25). No reproductive organs formed on 

 these pieces. The bands persisted until the hydranths dropped 

 off. This serves to demonstrate that the small distal piece A 

 when connected with the proximal piece is capable of developing 

 new structures after the tentacles have been laid down. It also 

 shows that the "red stuff" which is seen in the ridges, is not used 

 again when a new row of tentacles is laid down. Stevens ('02) and 

 Child ('07c) have observed in the proximal piece, after separation 

 of the two ridges, that the "red stuff" which was originally in 

 the proximal row forms a mass at the end of the stem, and when 

 the hydranth is completed the mass is ejected. 



8 REMOVAL OF THE ENTIRE PRIMORDIUM 



Driesch ('02) found when he removed the early anlage of the 

 hydranth by a cut just below the proximal row, that in a large 

 number of cases the ridges disappeared, and a new anlage devel- 

 oped, the latter being much reduced in length. Thus the length 

 of the "reparation area" bore a definite relation to the length 

 of the piece. Child ('07a) has also shown that there is a reduc- 

 tion in length of the primordia in short pieces, but the reduction 

 in length is not proportional to the reduction in the length of the 

 piece. 



I have made a series of experiments in which long pieces were 

 cut from the stems of different individuals, and after the tentacle 

 aniage appeared, the distal end of the piece was removed by a cut 

 below the proximal tentacles (Fig. 26, X). I hoped to find that at 



