No. 423.] HYDRACTINIA AND PODOCORYNE. I99 
but after the colony was well formed a few small reproductive 
polyps also grew out from the stolons at occasional intervals 
(Fig. 5). -Although the colony lived for several days or a week 
after the production of the reproductive polyps, no signs of 


Fic. 6. — Represents a luctive polyp which t from the hydrorhiza July 20. Several 
generative buds were removed; two were left (g.). The reproductive tentacles were 
replaced by four nutritive tentacles (nt). Two small knoblike wen () are seen 
below the patritive tentacles 
t) g l end, fastening the individual to the disk. pets ee 



developing generative buds appeared. Indeed, the life of the 
colony seemed spent, the stolons became more slender and 
broke apart, and the polyps died, one after another. During 
the period of growth the stolons often anastomose and two 
adjacent colonies become united. Such colonies are most 
easily started if whole polyps are cut off close to the hydro- 
rhiza. A small piece of a polyp will lie on its side on the 
bottom of the dish, often producing new hydranths and chang- 
ing its form, until it disintegrates, but rarely forms stolons. 
In the same way reproductive polyps were removed and 
kept in dishes, with the hope that they would also form 
colonies. They sent out stolons much more slowly than the 
nutritive polyps did, and although a large number of individu- 
als formed stolons, many of them died before new polyps had 
developed. It is probable that others, which seemed more 
vigorous, might have developed new polyps had more time 
been allowed them. In one dish in which half a dozen repro- 
ductive polyps had formed stolons a curious change was 
observed. The stolons had grown rapidly, and the hydranths 
