588 | SUPPLEMENT 
and that they appeared to adhere more closely to the sub- 
marine rocks, the-greater the efforts that were made to detach 
them. ‘They considered the sponges to be organized bodies, 
intermediate to vegetables and animals, such as they subse- 
quently named zoophytes. This opinion was maintained for 
along time, and gained the assent of most of the Italian 
writers, Spallanzani, Olivi, &c. some of whom, however, 
granted a higher degree of animality to these productions. 
Rondelet seems to have been the first who utterly refused all 
sensibility to the sponges, and denied the fact mentioned by 
Aristotle, above alluded to. From this an hypothesis arose, 
that they were only vegetables, and it was adopted by Tour- 
nefort, by many ancient botanists, and by Linnzus himself, 
in the first editions of his Systema Nature. Such, for a time, 
was also the opinion of Spallanzani, as far as some species 
were concerned, because he observed in them no signs of 
contractility. ‘The third opinion, which was Peyssonell’s, is 
that sponges are sorts of polyparia, fabricated by animals found 
in their excavations. But as this could not be supported, as 
these animals have no adherence with the sponges, and are 
often of totally different species, this hypothesis was modi- 
fied by pronouncing the sponge to be a polyparium, the polypi 
of which are unknown. 
If naturalists still hesitate respecting the nature of the 
sponges, it is, doubtless, because they have no sufficient no- 
tion of their organization. Without touching on the merits 
of the controversies concerning them, we shall lay before our 
readers all that is known upon the subject. 
Every one agrees that the sponges are generally formed of 
at least two substances; the first, interior, more or less cor- 
neous, fibrous, intercrossing in all ways, and forming a sort of 
felt-like tissue, more or less compact. It is this which at- 
taches the sponge to the submarine bodies; the second, soft 
or gelatinous, enveloping the preceding, forms a sort of general 
