CLASSIFICATIONS OF ZOOPHYTES. 
77 
gelatinous, and the external a complete membrane, so formed as to cover the stem 
in the manner of a sheath or tube. That the other Gorgonise consist of a horny 
stem coated by a membrane, which is hardened by carbonate of lime. That the 
sponges are of a nature similar to the horny stems of the Gorgonise, and only 
differ from these and from each other by the quality of texture. And lastly, 
that the Alcyonia are likewise composed of a soft flexible membranaceous sub- 
stance, very similar to the cortical part of some of the Gorgoniae ; and in like 
manner slightly hardened by carbonate, mixed with a small portion of phosphate 
of lime. 
“ From this mass of evidence we collect, in general, that the varieties of bone, 
shell, coral, and the numerous tribe of Zoophytes with which the last are con- 
nected, only differ in composition by the nature and quantity of the hardening 
or ossifying principle, and by the state of the substance with which this princi- 
ple is mixed or connected ; the gluten, or jelly, which cements the particles of 
carbonate or phosphate of lime, and the membrane, cartilage, or horny substance 
which serves as a basis, appearing to be only modifications of the same sub- 
stance, which progressively graduates from a viscid liquid, or gluten, into a ge- 
latinous substance, which again, by increased inspissation, and by the more or 
less perfect degrees of organic arrangement, forms the varieties of membrane, 
cartilage, and horn, which, it seems, form the peculiar differences of the several 
species.” Abst. Phil. Trans, i. 25-26. There is a very full analysis of Hatch- 
ett’s paper in Thomson’s Syst. of Chem. v. p. 559, et seq. The paper itself 
will be found in Phil. Trans, abridg. xviii. p. 706. 
Raspail has ascertained that a large proportion of iron enters into the com- 
position of the Alcyonella, which he thinks may be derived from the habitat, the 
zoophyte developing itself upon ferruginous rocks. The iron holds the same po- 
sition in the polypidom, that the carbonate of lime does in the Oculinse, or the 
crystals of silex in the sponges. Its great proportional quantity may be esti- 
mated from the following experiment “ Un fragment sec du Polypier faisait 
devier de trois degres la nouvelle aiguille aimantee, construite par notre collegue, 
M. Saigey, quoique ce fragment ne presentat a l’aiguille qu’une surface d’un cen- 
timetre environ. Cette deviation paraitra enorme si l’on veut se rappeler que 
l’Alcyonelle est une substance spongieuse extraordinairement legere ; ajoutes a 
l’importance de ce resultat que le fer paralt y exister a l’etat de trioxide, puisqu’ 
avant comme apres Vincineration, la substance est egalement rougeatre, et qu’en 
consequence son influence sur raiguille aimantee serait infiniment faible, si le fer 
existait en faible quantite dans son tissu lache et spongieux.” — Mem. de la Soc. 
d’Hist. Nat. iv. p. 119. 
“ Non tamen, post tot ac tantos scriptores, pigebit meam quibusdam locis 
posuisse sententiam. Neque enim me cujusquam sectae, velut quadam super- 
stitione imbutus, addixi sicutipse plurium in unum confero inventa, 
ubicumque ingenio non erit locus, curse testimonium meruisse contentus.” — 
Quintilian, iii. i. 
