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tion of the structures, as to render the whole of these fragile tissues 

 perfectly indistinct ; hut there was one interesting result from this 

 operation, which was, that from both surfaces of the sponge there 

 were forced out clusters of minute spherical and oval bodies, contain- 

 ing slight traces of granulations within; and along with these masses 

 there appeared, in several cases, cilia similar to those described in situ 

 within the diaphragm, and which continued their motion for a con- 

 siderable period, frequently with so much force as to give a slight 

 motion to the mass of small spherical bodies with which they were 

 connected. From the circumstances I have described I concluded 

 that the only way of proceeding, with any chance of success, would 

 be by carefully pulling the tissues asunder. I then took two 

 parallel holds of the sponge, at right angles to its long axis, with 

 fine spring pliers, and gently pulled it asunder ; and, after many 

 trials, I succeeded in getting several of them to divide in a tolerably 

 straight line ; and these I cut from the masses, as near the torn 

 edges as possible. I then placed the ring-like sections, as before, in 

 closed cells ; and, after many trials, I succeeded in finding some of 

 them with sections of cells which still retained their vital functions, 

 notwithstanding the terrible mutilation to which they had been 

 subjected. 



I found the whole length of the cell, from the inner edge of the 

 diaphragm to its termination near the outer surface of the sponge, 

 to be closely studded with tessellated, nucleated, cellular structure, 

 as represented at c, fig. 1 ; and from one or other among these 

 cells I observed several long and very attenuated cilia to spring, and 

 which kept up a rapid action for a considerable period. After a 

 while, as the vital energy of the sponge decreased, their motions be- 

 came much more languid ; and I then observed one in particular, 

 which continued for nearly half an hour to wave gently backward 

 towards the outer surface of the sponge, and then rapidly forward 

 towards the mouth of the diaphragm. In several others the direc- 

 tion of the motion was not so decidedly in the long axis of the cell ; 

 but this uncertainty of action might probably have arisen from par- 

 tial disruption of the tissue. 



In the cell thus described there were as many as nine cilia in 

 action together, situated in various parts between the two extremi- 

 ties ; but they did not appear to sympathize with each other in their 

 movements. I never succeeded in getting so many of these organs 

 in motion together, in any one cell, in the numerous specimens which 



