BONY STRUCTURE OF THE CORALLIDSE. 
223 
ization exists in the nearly allied tribe of the Corallidse, and that from the bases of 
the minute polyps, the chyliferons juices should be dispersed in every direction through 
the common mass of the stony body of the animal, and that the usual processes of the 
absorption and reproduction of parts should take place within their calcareous axes, 
as in the corresponding parts in the higher tribes of animals. 
The structures which I have described are in other respects exceedingly interest- 
ing, as they establish a degree of organic connection between the Corallidse and the 
Spongiadse, which had not, I believe, before been suspected to exist, and at the same 
time have a tendency to confirm the idea of the animal nature of the latter. What- 
ever doubts may have existed at former periods in the minds of naturalists respecting 
the nature of the siliceous spicula of the sponge tribe, the fact of having found these 
curious organs so exactly similar in every respect amid the undoubted animal secre- 
tions of the Corallidse, will stamp them as true animal productions. The vascular 
tissue with csecoid appendages has a striking resemblance to that which I have de- 
scribed in Part I. vol. i. of the Transactions of the Microscopical Society, as found 
upon the fibres of one of the species of the sponges of commerce ; and in the fleshy 
portions of Tethea lyncurium and Geodia Zetlandica, Lamarck, we find fleshy mem- 
branes, with minute vessels meandering through their substance in every direction, 
so closely resembling those obtained from the coral tribe, as to establish a degree of 
affinity between the Corallidse and Spongiadse so intimate as to appear to place the 
animal nature of the latter beyond a reasonable doubt. These tissues are in a like 
manner common to Nullipora. How far this may be the case with other apolypous 
corals remains yet to be proved ; but should the same structures prevail in these as in 
that genus, it would go far to prove these curious bodies to be animals, instead of 
being, as heretofore considered, vegetables secreting calcareous matter in unusual 
quantities. 
The cellular tissue of the Nuliiporidse is certainly, as regards both sponges and 
corals, anomalous, but the membranous and vascular tissues which accompany it are 
in an equal degree contrary to the types of the corresponding organs in any esta- 
blished vegetable body with which I am acquainted. Their true position in the scale 
of organization would therefore seem to be between the Corallidse and Spongiadse ; 
abounding in membranous and vascular tissues, like those of the former, but totally 
destitute of polypiferous organisms, like the latter ; while the cells and their accom- 
panying cytoblasts are but a more methodical development of the same laws that we 
observed in operation in the membranous portions of almost every coral that was ex- 
amined. 
