638 PROFESSOE E. EAT LANKESTEE. 



the young bud itself. Another septum will not be formed 

 until the stalk has grown to a certain additional length. Thus 

 in fig. 3, the stalk must elongate considerably between buds 2 

 and 3, and then a septum will be formed just behind bud 2 ; 

 subsequently growth of the stalk will occur between buds 1 and 

 2, and then a septum will be produced behind bud 1. In the 

 meantime the leading polypide-bud will have moved forward, 

 forming new segments to the tubarium, and probably new rudi- 

 ments of buds will have appeared between the present bud 

 No. 1 and the leading bud. I am inclined to think that the 

 leading polypide-bud does not advance so rapidly to its complete 

 form as do the buds lower down the stalk, which are not called 

 upon as this is to act as the leading growth of a pro- 

 liferous branch. It seems likely (from the fact that this 

 special form was often observed) that the leading bud is arrested 

 in the condition shown in figs. 1 and 3 for a certain time, i.e. 

 during the period of proliferation, and that only when its stalk 

 ceases to be proliferous does the terminal bud go on to complete 

 its own development. Apparently the completed polypide/in 

 PL XXXIX, fig. 1, is actually of later origin than the leading 

 immature polypide b ; that is to say, it was formed as a bud 

 on the stalk of this leading bud. 



With regard to the formation of branches — that is to say, 

 the acquirement of the bud-producing faculty by the portion 

 of stalk supporting any given polypide, in virtue of which 

 faculty the polypide-stalk at once becomes an axis or branch 

 — 1 am inclined to think that it must be determined at 

 an early period in the growth of the given polypide. I 

 cannot find evidence of any complete polypide, here or there, 

 in the colony, taking upon itself bud-production, after the 

 complete development of the polypide. Such a thing may 

 occur, but I have no evidence of it. It would appear that a 

 branch is started by such a polypide-bud as No. 6 in fig. 3, 

 PL XXXIX, breaking its way through the tubarium, and 

 instead of itself developing and forming an upright tube, its 

 stalk appropriates the nutriment, elongates disproportionately, 

 and produces lateral buds. A branch may form at auy point 



