Sro BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
would be one or two free broken ends for each piece, but one does not 
find it so. Occasionally a single free end may be found but scarcel 
ever two free ends on the one piece. ; 
In the case of the growing end of the stolon it appears that since 
there is no longer any inducement to continue in the same general 
direction in which growth has previously taken place, on account of 
which thus terminates the stolon and leaves no free growing end. The 
lack of free broken ends seems bewildering at first and it seems per- 
missible to conclude that here is something new in hydroids, viz: 
colonies developing from planulae at the surface of the high seas, for 
how could so many colonies, perfect ones at that, appear if they had 
been broken away from their regular support. Further examination 
Fic. 74.— Clytia cylindrica. 
brings out the fact that regeneration is responsible for the deception, 
but conditions must be very favorable for such regeneration since in 
almost every instance a zooid is growing out from the broken end ae 
all are in good condition. In many cases the regenerated porti 
so nearly equal in size to the original part, both in the perisare and in 
the coenosarc, that it is difficult to detect the junction and hence the 
deception is complete. In other cases the regenerated part is sii 
ciently smaller to be readily noticed. 
Besides the zooids that grow out from the broken ends, ols 
appear to have developed in the regular way after the separation from 
the support, as, instead of coming off regularly in the one direction, 
they may come off on any side of the stolon to make the colony de- 
cidedly irregular (Fig. 73). Commonly when a straight piece of 
stolon regenerates, a zooid grows out from each end in line with the 
stolon itself, while the zooids Ss hei attached were at right angles 
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