IQ2 C. M. CHILD. 



of stolons, but my observations suggest that in general stolons in 

 contact grow to greater lengths and perhaps more rapidly than 

 those free in the water. In the figures all the longer stolons are 

 in contact with the glass of the container over most of their 

 length (Figs. 2, 5, 10, 14, 18). The adventitious stolons in 

 Figure 13 and the short stolons of Figures 1-5, 7, 8, etc., are not 

 yet in contact with surfaces. 



The stem grows only as part of a hydranth-stem complex or 

 gradient, while the stolon may continue to elongate indefinitely 

 without developing hydranths or hydranth buds. The direction 

 of growth of stolons is apparently indefinite, or at least is readily 

 altered, but the stem is usually straight. And finally, in those 

 species in which annulations of the perisarc appear on the stems, 

 the stolons are not annulated. 



The "intermediate" outgrowths observed in Gonothyrcea in 

 HC1 (p. 190 and Fig. 12) resemble stems in their rigidity and def- 

 inite direction of growth, but, except in the development of the 

 first hydroid from the planula, stems do not grow out in this 

 manner without at least a hydranth bud at the tip. If the differ- 

 ence between stolon and stem is primarily one of "steepness" 

 or other difference of the gradient, such intermediate outgrowths 

 are possible and there is no good reason for doubting that the 

 outgrowths observed are really intermediate. 



THE PROCESS OF TRANSFORMATION. 



The first step in the process is the inhibition or depression of 

 the hydranths. The changes in the hydranths differ according 

 to species and degree of depression, and range from decrease or 

 cessation of motor activity for a day or two with subsequent 

 recovery to complete disintegration or resorption. In Bougain- 

 villea all the original hydranths usually disappear, even in stand- 

 ing water, within twenty-four to thirty-six hours and new 

 hydranths may begin to develop within forty-eight hours. In 

 Gonothyr&a, on the other hand, the change from natural condi- 

 tions to standing water has little effect on the hydranths; they 

 remain intact for a week or more in most cases, but finally disin- 

 tegrate or are resorbed as starvation advances. 



The older, fully developed hydranths apparently always die 

 and disintegrate, at least in large part, in all the species observed, 



