184 C. M. CHILD. 



buds of the more basal regions, usually not more than the basal 

 third or half, or as adventitious outgrowths from the branches 

 of these regions. What factors are concerned in such cases is of 

 course uncertain, but it may be pointed out that in these basal 

 regions, which are often over-grown with plants and protozoa, 

 less favorable conditions for respiratory exchange retarded 

 water movement, accumulation of CO 2 , lack of oxygen may 

 directly inhibit and transform hydranth buds into stolons. On 

 the other hand, if the whole stock is exposed to inhibitory condi- 

 tions, the more basal regions, because of their lower rate of metab- 

 olism (Child, '19, '21; Hyman, '20), are in general less able to 

 acclimate to such conditions than the more apical regions and 

 may, therefore, undergo transformation, while other levels of the 

 stock do not. Stocks which show no stolons at any level above 

 the basal end when collected usually develop stolons over more 

 or less of the stock after a day or two in standing water. 



That such development of stolons from the more basal regions 

 of stocks in water is not due to the presence or accumulation of 

 "stolon-forming substances" in these regions or to any other 

 specific factor is shown by the fact that this transformation can 

 be induced in any or all regions of the stock, according to experi- 

 mental conditions. The following experiments serve as examples: 



1. Pieces of stocks in ethyl urethane, m/2OO. After forty- 

 eight hours all hydranths disintegrated and numerous stolons 

 developed, chiefly apical (Fig. i) or subapical (Fig. 2). 



2. Pieces in ethyl urethane for twenty-four hours, then re- 

 turned to well aerated sea water. In ethyl urethane all original 

 hydranths disintegrated and stolon development began. After 

 twenty-four hours in water many subapical stolons were present, 

 but new hydranths were developing and some stolons were 

 transforming into hydranths and stems. 



3. In ethyl urethane m/$oo the original hydranths disinte- 

 grated and apical and subapical stolons developed within twenty- 

 four hours, but after forty-eight hours many apical ends and in 

 some cases the first subapical bud developed new hydranths and 

 the stolons were inhibited (Fig. 3). 



4. Pieces in ethyl urethane m/$oo twenty-four hours, then 

 returned to water, gave much the same results, except that in 

 some cases the tips of the apical stolons themselves transformed 



