TRESH-WATEE SPONGES. 183 



CTer so slightly by any such little body, it is caugbt immediately and 

 conveyed to the mouth. One may observe the creature, when disap- 

 pointed of its prey, slowly extending itself again without retiring into 

 its case. 



" The bells or colonies of these animals are to be found adhering to 

 the large leaves of duckweed and other aquatic plants ; and may easiest 

 be discovered by letting a quantity of water, with duckweed in it, 

 stand quietly for three or four hours in glass vessels, in some window 

 or other place where a strong light comes ; for then, if any are about 

 the duckweed, they wiU be found, on careful inspection, extending 

 themselves out of their cases, spreading their plumes, and making an 

 elegant appearance. 



" They are extremely tender, and require no little care to preserve 

 them; their most general disorder is a kind of slime or mouldiness, 

 which wUl sometimes envelope them in such a manner as to prove 

 mortal. The best way of curing this is by gently pouring a large 

 quantity of water (perhaps two or three quarts) into the vessel where 

 they are kept, and letting it run ofi slowly ; by which means the slimi- 

 ness will gradually be loosened, and carried away with the water. 



" As to food, if fresh water be given them daily, they will find suffi- 

 cient for themselves ; and it is dangerous to try any other way of feed- 

 ing them ; for the smallest worms, or other visible insects one can think 

 of giving them, will tear their delicate frame in pieces.'' 



In the journal of the Bombay branch of the Koyal Asiatic Society 

 for 1849, Surgeon H. J. Carter gives a minute and able account of the 

 fresh-water sponges in the water-tanks of Bombay. Of five species 

 that he discovered, one was the SpongiMa friabilis, the others he named 

 Sp. cinerea, Sp. aUia, Sp. meyeni, Sp. plumasa. 



SpongiUa cinerea is stated to present on its surface a dark, rusty, 

 copper colour, lighter towards the interior, and purplish under water. 

 It throws up no processes, but extends horizontally in circular patches, 

 over surfaces two or three feet in circumference, or accumulates on 

 small objects ; and is seldom more than half an inch in thickness. It 

 is found on the sides of fresh-water tanks, on rocks, stones, or gravel. 

 Seed-like bodies spheroidal, about l-63d of an inch in diameter, pre- 

 senting rough points externally. Spicula of two kinds, large and small ; 

 large spicula, slightly curved, smooth, pointed at both ends, about 

 l-67th of an inch in length; small spicula, slightly curved, thickly 

 spiniferous, about 1 -380th of an inch in length. 



SpongiUa friabilis. — Growing in circumscribed masses, on fixed 

 bodies, or enveloping floating objects; seldom attaining more than 



