87 
the rocks. This opinion of their possessing a degree of animal life 
was also entertained in the time of Pliny, Count Marsilli,* confirmed 
this opinion by observing, on their being taken out of the sea, a sys- 
tolic and diastolic motion, in certain little round holes, which lasted 
until the water they had contained was quite dissipated. Mons. 
Peysonell supposed sponges to have been formed by certain worms, 
which inhabited the labyrinthean windings of the sponge ; and be- 
lieved that whatever life was found in these substances, existed in 
these worms, and not in the substance of the sponge, which he was 
convinced was an inanimate body. This point was, however, deter- 
mined by Mr. Ellis, who, in a letter to Dr. Solander,-)- relates the 
observations which he had made ; by which he ascertained that these 
worms, which he found in the sponge in great numbers, were a very 
small kind of nereis, or sea scolopendra; and that they were not the 
fabricators of the sponge, but had pierced their way into its soft sub- 
stance, and made it only their place of retreat and security. Upon 
examining, in sea water, a variety of the crumb of bread-sponge, the 
tops of which were full of tubular cavities or papillae, he could plainly 
observe these little tubes to receive and pass the water to and fro ; so 
that he inferred that the sponge is an animal sui generis, whose mouths 
are so many holes or ends of branched tubes, opening on its surface ; 
with these, he supposes, it receives its nourishment, and discharges, 
like the polypes, its excrements. 
Mr. Ellis also discovered that the texture is very different in diffe- 
rent species of sponge; some being composed wholly of interwoven 
reticulated fibres, whilst others are composed of little masses of straight 
fibres of different sizes, from the most minute spiculae to strong elas- 
tic shining spines, like small needles of one-third of an inch long ; 
besides these, he observes, there is an intermediate sort, between the 
* Histoire Physique de la Mer, P. 53. 
t Phil. Trans. Vol. LV. P. 280. 
