78 PROCEEDINGS OF SOCIETIES. 
Further Report on the Vitality of the Spongiade. 
By Mr. BowErBank. 
Tue author stated, that in his former Report he had 
detailed a series of observations on the inhalation through 
the pores and the exhalation of water through the oscula of 
a marine sponge, Hymenacidon caruncula, and that he was 
enabled to determine with certainty the capability which 
that sponge possesses of opening and closing the oscula at its 
pleasure, but that he could not in that series of observations 
satisfactorily determine the nature and powers of the imbi- 
bing pores, as those organs can only be seen distinctly in ope- 
‘ation Im very young and transparent specimens; he there- 
fore commenced a series of observations on the action of 
the pores in young specimens of Spongilla fluviatilis on 
the 3d of October, 1856. He found that in a specimen 
about half an inch in diameter, which had attached itself to 
a watch-glass, there was at the summit of a large oval infla- 
tion, which varied its form remarkably within a very short 
time, a single osculum which opened or closed in accordance 
with the necessities of the animal, and from which when in 
full action a powerful stream of water was poured forth. 
The inhalation of the water by the porous system presented 
some remarkable peculiarities. When in a state of repose 
the dermal membrane appeared to be completely imperforate. 
but when about to commence vigorous inhalent action, a 
slight perforation appeared here and there over its surface, 
the orifices gradually creased in size until the full diameter 
of the pores were attained, and their margin then became 
thickened and rounded. And if a little indigo be infused in 
the water, it is seen to be absorbed with avidity, and the 
inhalent action continued for a considerable period, the inte- 
rior of the sponge becoming strongly coloured by the indigo. 
After a time the rapid inhalent process ceased, either 
abruptly or gradually, and a very languid action only re- 
mained, and nearly the whole of the pores were closed ; 
when this operation was about to take place, the rounded 
margin of the orifice lost its form and became thin and 
sharp, and the circumference gradually melted inwards until 
the orifice was entirely closed, and not the slightest indica- 
tion of the organ previously existing remained,—the opera- 
tion of closing occupying rather less than a minute. When 
once closed these orifices do not appear to be re-opened, but 
fresh pores are produced in accordance with the necessities 
of the animal. The colouring matter absorbed during the 
period of active inhalation was apparent in the sponge from 
twelve to eighteen hours, and during this period the stream 
