186 C. M. CHILD. 



into hydranths after return to water (Fig. 4; //, hydranth bud). 



5. In MgSC>4 m/^oo almost all hydranths were disintegrated 

 and subapical stolons grew rapidly within forty-eight hours 



(Fig. 5)- 



6. In MgSO 4 m/iooo disintegration of hydranths occurred 

 and stolons developed much as in Expt. 5, but after forty-eight 

 hours many new apical hydranths developed (Fig. 6; h, hydranth 

 bud). 



7. In sea water controls of Expts. 1-6 after forty-eight hours 

 the original hydranths were more or less affected : tentacles were 

 undergoing reduction or were completely gone and some hyd- 

 ranth bodies were disintegrated or disintegrating, or, in the case 

 of the younger hydranths, resorbed. Subapical, or even apical 

 stolons appeared on those axes in which* the terminal hydranths 

 were reduced or disintegrated (Fig. 7) and rarely short stolons 

 appeared on stems with persistent hydranths (Fig. 8). On some 

 stems new hydranths were developing Fig. 7, //). 



8. In KNC m/ioooo hydranths became motionless within a 

 few hours and in the course of three or four days disintegrated, 

 but in the course of six days no stolons developed. Solution was 

 then changed to m/2OOOO and left exposed to air to permit slow 

 decrease in concentration. A few short, subapical stolons de- 

 veloped during the next eight days, but no development of new 

 hydranths occurred and medusa buds underwent resorption. 

 Evidently development and growth were almost completely in- 

 hibited by this concentration. 



9. In KNC W/25OOO older hydranths disintegrated and younger 

 underwent resorption. Stolons developed in subapical and lower 

 regions. After six days solution was changed to m/ 50000 and 

 left exposed to air. During next eight days an extensive stolon 

 system developed from nearly all apical ends of all stems and 

 branches and also from basal cut ends of pieces. No hydranths 

 were present but a few hydranth buds appeared on the stolons. 

 Results essentially like those of following experiment. 



10. In KNC W/5OOOO the original hydranths disintegrated and 

 stolons appeared and after six days small, partially inhibited 

 new hydranths were present (Fig. 9). Solution was then changed 

 to m/iooooo in open dishes to permit gradual decrease in concen- 

 tration. During the next eight days the new hydranths were 



