ON THE VITAL POWERS OF THE SPONGIAD.E. 449 



A- an inch broad, the greatest thickness being about y^th of an inch, laying 

 open three large ex-cinreiit canals, and numerous other small canals and 

 cavities, and then replaced it in the water. I also cut seven other specimens 

 in halves, and then replaced them in the water, bringing the sections into close 

 contact. June 14th, at 10 o'clock a.m., I found the two pieces firmly 

 cemented without contact of the dermal membrane. On examining the sponge, 

 from the top of which I had cut oft' a slice at 12 o'clock, June 13, at 5 o'clock 

 on the same day, I observed that the three great orifices arising from sections 

 of great ex-current canals were each in process of being closed. From the 

 circular margin of each a membrane had extended from the circumference 

 towards the centre, very nearly closing the smallest of the orifices, and in 

 the other two cases leaving in one a circular central orifice, one-third of the 

 original diameter, and in the other about one-fourth of the diameter. On the 

 following morning, June 14, these apertures were entirely closed, and over 

 the whole of the wounded surface a new dermal membrane had been formed, 

 which securely closed ail the numerous small orifices as well as the larger 

 ones. 



The seven larger sponges which I had separated by cutting into halves, 

 and then replaced in water with the divided parts again in close contact, were 

 all found firmly united at 10 o'clock on the following morning, June 14th ; 

 and at June 15th, 10 a.m., the reparation of the subjects of the above 

 experiment were so complete as to quite obliterate the traces of the separation 

 in some of them. I therefore pickled the specimens. In other cases I cut 

 the same species of sponges into three pieces and reversed the position of the 

 middle piece of each, so as to render the sections unconformable ; but this 

 reversal of position, when the surfaces were brought into close contact, did 

 not seem in the slightest degree to retard the healing process, or to render 

 the adhesion of the pieces less firm than when placed together conformably. 



Disease and Death. 

 July 1. — At 10 A.M. I observed in one of the specimens of Hym. carun- 

 cula which I had brought from Tenby to London, an appearance of 

 disease in one of the lobes of the sponge for about half an inch from 

 the point inwards. There was a tumid appearance of the surface tissues 

 and a glassy opalescence in the part aff"ected. On smelling this portion of 

 the sponge, there was a slightly fcetid odour which did not exist in the 

 healthy portions of it. I immediately cut off this piece about half an inch 

 from the diseased part, and placed it in a basin by itself in sea-water. In six 

 hours the diseased appearance had become much more evident, but the 

 healthy part attached to it remained apparently unaffected. On examining a 

 section from the surface of the most diseased part, I found the dermal mem- 

 brane distended by an effusion of an opalescent lymph-like Huid ; thesarcode 

 in the immediate neighbourhood had lost its red colour, and the parts were 

 apparently in a decomposing state, but the adjoining portions of the same 

 tissue presented a healthy appearance. The separation of the diseased piece 

 from the parent sponge, had apparently been effective in preventing the 

 spread of the disease, as it retained its usual appearance at the section and 

 in the other parts of the sponge during the next twenty-four hours, but 

 shortly after that time, it began to exhibit strong symptoms of disease, and 

 in a few hours it was evidently dead. 



Nutrition. 

 I cannot dismiss the subject without a few words regarding the nutri- 

 tion of the Spongiadfe. That they inhaled and exhaled water abun- 

 1856. 2 G 



