10 
UKNATELLA GRACILIS, A FRESH-WATER FOLYZOAN. 
remains of brunches as empty cup-like processes, I Imve been led to suspect that the 
brandies are spontaneously and habitually detached from the parent stem, to become 
elsewhere attached, and thus form new colonies. The separation I have not actually 
observed, nor have I had an opportunity of ascertaining if such is the fact, since the 
suspicion occurred to me. The specimens which have come under observation, as 
illustrated by the accompanying drawings, exhibit every step of the process, so as to 
render the view at least probable. In further confirmation of it, I may add that in one 
instance in which I placed a number of profusely branching specimens of Z^rnatella 
in an aquarium, after a few days I noticed that they had been shorn of most of their 
branches, but whether this was the natural healthy course in the life of the animal, 
or due to unfavorable circumstances, I am not ready to decide. 
y. Voung UrnntelUi, in which the two .segments 
next the polyp-bell give off" buds and branches. 
4. 1 oung Urnatella, giving off both primary and secondary 
branches. Buds are also seen given from the latter. 
llie ,,oIyp.|R..d, or |,olyp.boU, of UrmrieUa (see figure .3), which terminates tl.e 
main stem im.l its bmnehes, when in active condition, appears as a hell-slmped laalv 
with a widely expanded oval or nearly eireular month, directed obliquely to one side 
m ven rally. The mouth of the hell is bordered by a broad waving band or colkr 
i om the inside of which springs a eirole of tentacles. Of these there are iisuallv 
sixteen though sometimes I have counted fourteen and twelve. They are cvlindiicai 
musenlar in eharaeter, diverge on each side to ihe inner s^LI^f tlZumlmbi^;;; 
speimn::":,^ ^ 
PP to be fuimshed with minute scattered tubercles. 
