ON THE VITAL POWERS OP THE SPONGIAD^. 44i 



Finding that this sponge, which M'as 2 inches in length, 1 inch in breadth, 

 and I of an inch in thickness, was by far the most interesting and active in 

 its habits, I determined to direct my observations more especially to its 

 proceedings for the future, and I accordingly separated it from the others 

 and placed it in a saucer full of salt water fresh from the sea, and put a few 

 small green fuci along with it. In 7 minutes after immersion in the cool 

 fresh salt water, the ex-current action again commenced slowly ; the closed 

 oscula gradually expanded, but not fully and completely, and the action was 

 steadily and moderately sustained ; at a quarter to 12 the action was so strong 

 and vigorous as to again cause a considerable elevation of the surface of the 

 water above the central and most active osculum of the largest sponge. It 

 is evident, therefore, that temperature has much to do with the activity of its 

 action, and that the animal is quickly cognisant of such changes, and is rapidly 

 amenable to the stimulus of a fresh and cool supply of the element in which 

 it exists ; and it is equally evident that its actions are not merely mechanical or 

 periodical, but subject to its own control, and that it can as readily avail 

 itself of favourable circumstances for imbibing nutrition or of protecting 

 itself from adverse circumstances, as the higher organized and more elabo- 

 rately constructed classes of animals. At 12 o'clock, on returning to 

 examine the state of affairs, I found the sponge perfectly quiescent, and some 

 of the oscula again closed. I immediately changed the water in this case, 

 pouring it full on the sponge in a large stream, and at 4 minutes after 12 the 

 currents were again in full action ; at 11 minutes after 12, the stream from 

 the central osculum was so forcible as to elevate the water to a considerable 

 extent at the surface immediately above it; at a quarter past 12 one of the 

 large groups of oscula commenced ejecting a stream so strong as also to pro- 

 duce an elevation of the water immediately above it. It would appear 

 therefore that the action of the different oscula is not simultaneous, but that 

 each is independent, to a considerable extent, of the other. At 1 o'clock, when 

 I left them, they were still in action, although slowly ; and on my return at 

 3 o'clock they wei'e all apparently quiescent, and remained so for the remainder 

 of the day. At 11 p.m. I drained the water from them, and left them so 

 for the night. 



June 6th. — At half-past 9 o'clock I put more sea-water to them. It had 

 stood some time in the sun, and was probably above the ordinary tempera- 

 ture. In about 5 minutes the ex-current action commenced, and proceeded 

 languidly for about half an hour, and then ceased. At half-past 12 1 drained 

 the water from it, and supplied it with water fresh from the sea, and the ex- 

 current action almost immediately recommenced, and at 1 o'clock was so 

 forcible that the surface above the two large groups of oscula was consider- 

 ably elevated by the force of the jets ; at a quarter to 2 o'clock the action 

 had entirely ceased. I drained off the water, and poured fresh water over 

 the sponge by jerks, until I had filled the saucer; again, in a few minutes, 

 action commenced in the large group of oscula near the largest end of the 

 sponge, and attained sufficient force to elevate the surface of the water by 

 the force of its jet at 6 minutes to 2 o'clock ; but this time it was the only 

 osculum in action, the smaller central one and the other large compound 

 osculum remaining quite inert, and the central one so completely closed, that 

 it was only by minute inspection with a 2-inch lens, and a complete familiarity 

 with the surface of the sponge, that [ could make certain of its precise posi- 

 tion ; at 20 minutes after 2 o'clock the central small osculum had opened, 

 and was sufficiently in action to elevate the surface of the water above it; 

 but the third, the large one at the smaller end of the sponge, was still inert, 

 and the small oscula within the large outer orifice were closely shut. At 



