376 CHAS. W. HARGITT. 



Again, after such prolonged periods there may come about 

 another direction of regenerative activity and a hydranth may 

 arise. Aside from the evidence of life observed in the active 

 circulation within the coenosarc of stolons it becomes easy for 

 one to recognize in the character of the cells of the various 

 structures the evidences of life or death, and furthermore death 

 of any portion is rapidly followed by disintegration brought 

 about by microorganisms. It should have been stated in the 

 earlier part of this section that the process of encystment usually 

 begins soon after the aggregation phase is complete, which may 

 be within twelve to tAventy hours, though it may not become 

 evident until much later, thirty to forty hours. The first 

 evidence of its formation is the adhesion of the mass to the 

 bottom of the glass, and somewhat later may be distinguished as 

 a very delicate transparent film covering the entire mass. Its 

 later extension may be easily followed as the growth of stolons 

 . takes place, which may be quite rapid in some cases, or in others 

 very slow. Here again as was pointed out in an earlier connec- 

 tion, there is a marked similarity in the aspects of regenerative 

 growth and those of embryonic development which further 

 emphasizes the probability that they are fundamentally identical, 

 having their initiative in potentially embryonic cells. 



Polyp Formation. — In Podocoryne the first evidence of definitive 

 hydranth organization was found during the second day following 

 the experiment. This consisted in the dissolution of the cyst 

 at its upper surface and the protrusion of a bud-like upgrowth. 

 At first these were barely distinguishable, but during the third 

 day they had become large enough to be seen with che unaided 

 eye. The first fully formed hydranth appeared early on the 

 fifth day, when a polyp haying the distinctive fornj. of hypostome 

 and three tentacles was noted. This was folloM^ed by further 

 growth of the young specimen in all its parts. Tf e movement of 

 the tentacles and their growth in length was interesting and strik- 

 ing, leaving not the least doubt as to the genuineness of the 

 regenerative process. Usually the first three tentacles appeared 

 at about the same time, but in a few cases it was noted that when 

 first observed there were but two, though a third appeared 

 rather soon after. The full six tentacles of the new polyp were 



