Rci^ciicrafioii in Hyilronicditsac 7 



ends. Moreover, the holdfasts formed with eijual facility from 

 both ends. One piece anchored itself to the bottom of the dish by 

 the distal end and then assumed an upright position. Several 

 hydranths formed from the branches and the proximal end of 

 the stem (fig'. 15). As already suggested, hydranths formed 

 rather slowly. The first one was completely regenerated at the 

 end of 42 hours, and after this they formed continually for ten 

 days. In this time 40 to 50 developed, though not all were 

 present at any one time. Some would form and degenerate or be 

 withdrawn into the perisarc and others form. 



ExPERi:\iENT 14. — Pciiiian'a from eel grass. — This experiment 

 was conducted at the same time and in the same manner as ex- 

 periment 13. The behavior of the pieces and the method of re- 

 generation were the same as in the precedmg experiment, hold- 

 fasts forming at the places of contact with about equal rapidity 

 and ease. The first hydranth was completely regenerated within 

 30 hours, though after the first they did not develop as rapidly 

 nor as abundantly. This may have been due to some harmful 

 efifect of the water, or more probably to a less healthy condition 

 of the stems. 



Experiment 16. — Pieces of Tiibularia crocca placed with the 

 distal ends in the sand as in experiment 11. — In about 18 hours 

 a hydranth had completely regenerated on the end of a branch 

 pointing downward ; 24 hours later three more had formed, two 

 of them on branches extending downward. After this, hydranths 

 formed on branches and on the ends of the main stems, i. e., at the 

 proximal ends. Sometimes the hydranths on the ends of droop- 

 ing branches hung downward ; at other times they turned and 

 grew upward. .In this experiment, as in experiment 11, there 

 seemed to be a strong tendency for hydranths to form at the 

 distal ends of branches rather than at the free (proximal) ends 

 of the stems, and when they formed on the end of the stem regen- 

 eration was much slower. 



Experiment 23. — Tubularia crocca cut in pieces of about 3 mm. 

 length and placed on the bottom of the dish. — No change was 

 noticeable for about two days and then in several pieces there 

 seemed to be a collection of red pigment at one end. No further 



2«I 



