Natural History of British Zoophytes. 75 
mere statement of the facts witnessed, or what seemed an unavoid- 
able inference from them ; but, perhaps, he deserted his usual cau- 
tion when, from analogy principally, he asserted that the articulated 
calcareous corallines (Corallina, Lin.) and sponges, of a very diffe- 
rent structure from coral, madrepore, or the horny corallines, were 
also like them, manifestly the places of abode of different species of 
polypes. In the former (Corallina) he had indeed detected some 
slender fibres which, it was presumed, might be parts of polypes, 
but this observation he was never able to confirm, and it was rather 
because of the porous structure of the corallines, than from any thing 
else, that he inferred the existence of polypes in them, a structure 
which he had examined with minute accuracy and shown to be es- 
sentially different from any known vegetable tissue, and, secondly, 
because of their chemical constituents, of which he procured an ac- 
curate analysis to be made. With regard to the Sponges, Ellis, as 
Peyssonnel had previously done, supposed at first that the regular 
holes observable in dry specimens, strongly indicated their being 
once filled with animals ; but when after repeated examinations of 
recent sponge, he could detect none, this conjecture was abandoned, 
and so thoroughly was he afterwards satisfied of the non-existence 
of animalcules, that he combated the opinion of those who maintain- 
ed the contrary, pointing out where the error lay in mistaking small 
insects which had crept into the sponge in search of food or shelter 
for the real inhabitants and fabricators of the zoophyte. Yet not 
the less was Ellis convinced of its animality ; its chemical consti- 
tuents and its structure were to him conclusive proofs of this fact, 
particularly when added to the signs of irritability he saw them ex- 
hibit when in a fresh state. " I am persuaded," he writes to Lin- 
naeus, " ihejibrce inlertextce of sponges are only the tendons that en- 
close a gelatinous substance, which is the flesh of the sponge. Mr 
Solander and I have seen the holes or sphincters in some of our 
sponges, taken out of the sea, open and shut while they were kept 
in sea- water ; but discovered no animal like a polype, as in the Al- 
cyonium manus mortui." And again " I attended last summer in 
pursuit of the animals in sponges, but believe me there are none : 
but the whole is an animal, and the water passes in a stream through 
the holes, to and fro, in each papilla."* 
* Lin. Corresp. vol. i. p. 161, and p. 163. In a subsequent letter Ellis ex- 
plains himself more fully. " I am now looking into the nature of sponges, and 
think by dissecting and comparing them with what I have seen recent, and with 
the Alcyonium manus mortua, that I can plainly see how they grow ; without 
trusting to Peyssonell's account of them, which is printed in our Philosophical 
