442 REPORT — 1856. 



37 minutes past 2 the third osculuiu had opened, and the whole three were 

 in strong action, each projecting a stream so strong as to elevate the surface 

 of the water above it. This independence and inequality of action is remark- 

 ably curious. I left them in the above-described state of full action at 15 

 minutes to 3 o'clock. On my return at a quarter past 3, action had entirely 

 ceased, the group of oscula at the small end of the central osculum were 

 closely shut up, but in the group at the largest end of the sponge the mouths 

 of the oscula were open, but apparently entirely inert. At half-past 1 1 p.m. 



1 drained off the water for the night. 



June 7th. — I put fresh water to the same sponge at half-past 9. No action 

 was observed until half-past 10 ; it was then very languid, and ceased entirely 

 in a very short time ; at a quarter past 12 I again drained off the water, and 

 poured fresh cool water on the sponge; in about 10 minutes the ex-current 

 action commenced from the two large groups of oscula near the ends of the 

 sponge, and in a very short period, about 10 minutes, the action became so 

 strong as to produce the elevation at the surface of the water immediately 

 above them. During this period the small osculum in tlie middle of the 

 sponge was closed and entirely inert. I did not examine it again until 



2 o'clock, when the action had ceased ; at 1 1 p.m. I poured off the water as 

 usual. 



June 8th. — At 10 o'clock I poured fresh sea-water over it and filled the 

 saucer as usual ; within one minute it commenced ejecting granules of effete 

 matter from the two large oscula, and in a few minutes the action was strong 

 enough to produce the usual elevation at the surface of the water. I looked 

 carefully with a 2-inch lens for the central osculum, but could not detect it, 

 and it had all the appearance of having been permanently closed by a mem- 

 brane. When in full action the membranous margins of the oscula are 

 tense and very distinctly defined ; but when the action becomes languid or 

 ceases, the orifices contract to about half the diameter they assume in an 

 active state, the marginal membranes lose their tension, and the edge becomes 

 very indistinct. Previously to a general cessation of action, it will sometimes 

 occur that one or two of the oscula of the group will assume this inert and 

 flaccid appearance, while from one only the stream will continue to issue in 

 full force, and this condition was assumed by the two large compound oscula 

 this morning at 12 o'clock. 



It is a remarkable circumstance, that of eighteen other specimens of the 

 same species of sponge which were treated in precisely the same manner as 

 the one whose history I have just recorded, three only of them had assumed 

 ex-current action up to 12 o'clock on the 8th of June. It is evident therefore 

 that the commencement or the cessation of action is not a merely mechaniial 

 effect, arising from temperature, or the general effect of particular circum- 

 stances, but that, as in other animals, each individual commences or ceases 

 action as may be dictated by its especial necessities. 



At 8 minutes past 12 o'clock the osculum at the large end was still in full 

 work. At a quarter to 1 o'clock the osculum at the small end had resumed 

 action, and in the mean time no cessation had occurred in the action at the 

 large end. At half-past 1 o'clock I left both groups of oscula in steady 

 action, each producing its elevated spot on the surface of the water. On my 

 return at 4; o'clock they appeared perfectly quiescent. I immediately poured 

 off the water and gave them fresh cool sea-water, and on looking at them 

 again at 5 o'clock, they were in very powerful action, and the middle single 

 osculum that had remained closed so long, had now opened and poured forth a 

 stream that raised a considerable elevation on the surface of the water, 

 and the osculum was fully expanded. At 5 o'clock the same osculum had 



