ON POLYPI. 581 
Previously to taking a short review of the principal groups 
of the CORALLIFEROUS PoLypt, &c., it may not be unne- 
cessary to say a few words in general on the bodies more or 
less solid, with which these animals are united, and which 
are now generally termed by naturalists Polyparia. ‘This 
term, of very general, perhaps too general an extension, may 
be thus defined. A polyparium is a fixed envelope, more or 
less solid, calcareous, or corneous, in which a polypus resides, 
and which is the evident result of a transudation from its 
body of an excretion through certain pores of its skin, of 
matters sufficiently composite to form, by their approxima- 
tion, aconcrete body more or less solid, and altogether inor- 
ganic. This definition, however, is strictly applicable only 
to the madrepores and eschare of Linnzus, and is not equally 
so to the other divisions. Therefore, if we persist in gene- 
ralizing this name, it will be necessary to define it as a solid, 
calcareous, or corneous, the residuum of one or several polypi, 
without any attention to its mode of formation, or the manner 
in which the polypi are placed there, and then the fibrous 
mass of a true alcyon, the fleshy mass of a pennatula, the 
corneo-calcareous lamina of an eschara, the plant-like stems 
of cellaria and sertularia, the calcareous, arborescent, fron- 
descent masses of the madrepores, will be equally polyparia. 
We may even add to these the beautiful tufts of the corallina, 
on the supposition that they support polypi, which, however, 
is by no means clearly made out. 
In considering the nature of polyparia, we find them to be 
of several sorts, according as they are calcareous, or stony, 
corneous, fibrous, corticiferous, gluey, or fleshy. 
The CORALLINES form a genus of organized bodies, on the 
nature of which, although it is very common in all the seas 
of Europe, and has for a long time been employed in thera- 
peutics, authors are by no means agreed, some regarding it 
as appertaining to the vegetable, and some to the animal 
