378 CHAS. W. HARGITT. 



anticipate that a similar type of reaction might be anticipated in 

 this connection, but as will be seen this expectation was not 

 realized fully. The early reactions in aggregation, encystment, 

 etc., were quite as prompt and promising as in Podocoryne. And 

 in these features the species showed nothing peculiar. But 

 beyond the initial stages the results were disappointing. The 

 mortality was much greater and the growth reactions much less 

 energetic. Experiments were varied in every way practicable, 

 hydranths alone being used for obtaining disorganized cells, 

 coenosarc alone, male colonies alone and female colonies alone. 

 There seemed to be no very marked differences in results, though 

 the cells obtained from crushing hydranths gave the least satis- 

 factory results. As already stated the early stages followed 

 quite as in Pocodoryne, encystment, and stolonization, but beyond 

 these my experiments were far less satisfactory than in the former. 

 In only a few cases was I able to obtain polyps, and these were 

 small and very weak. A few developed tentacles, but never the 

 usual number, nor were they more than buds on the base of the 

 hydranth. The few polyps which developed secreted the usual 

 perisarc, which was indistinguishable from that of an embryonic 

 Eudendrium. 



Tuhularia. — As in the former I employed two species, T. 

 mesemhryanthemum, and T. larynx. As in the former the early 

 reactions were prompt and quite like the others. But unlike 

 the others my experiments never afforded a single polyp. The 

 massing of dissociated cells was quite as prompt and the resulting 

 morula-like embryo as promising as in either of the others. 

 The encystment of perisarc followed in du,e order, and these lived 

 for many days, but they never showed /urther signs of develop- 

 ment. Perhaps no hydroid genus ha?/ had so large a place in 

 experimental work as has Tuhularia. If therefore my anticipa- 

 tions as to the behavior in cellular regeneration of Eudendrium 

 were disappointing, those concerning Tuhularia were really per- 

 plexing, at least for the time being. I think an explanation may 

 be ventured which, though not absolutely convincing, may relieve 

 a measure of the perplexity. It is to the effect that regenerative 

 potency in an organism is more or less conditioned by its state 

 of vitality, or in still more suggestive phrase, its physiological 



