516 CLASS ECHINODERMATA. 
petrous bodies pierced with pores, which have been thought 
to approximate to the millepora. If they were, in fact, 
enveloped with a bark, containing polypi, they would be 
moveable polyparia, and should rather be approximated to 
the pennatule. Such are 
The OvuLITES, Zin., in the form of eggs, hollow inter- 
nally, and often pierced at both ends; the LUNULITES, orbi- 
cular, convex, striated, porous on one side, and concave on 
the other; the ORBULITES, orbicular, flat, or concave, 
porous on both sides, or at the edges. If the DACTYLOPORA 
is free, as M. de Lamarck thinks, it would also appertain 
to this division. It is a hollow ovoid, open at both ends, 
with two envelopes, both pierced with meshes, like the 
retepora. 
In the fourth tribe, the animal bark encloses only a fleshy 
substance, without either osseous or corneous axis. 
ALCYONIUM, Linn., 
Have, like the pennatule, polypi, with eight denticulated 
arms, and intestines stretching into the common mass of the 
ovaries; but this mass is not sustained by an osseous axis. 
It is always fixed to the body, and when it is elevated into 
trunks or branches, we find nothing in its interior but a 
gelatinous substance, traversed by several canals, surrounded 
by fibrous membranes. The bark is harder, and hollowed 
with cellules, into which the polypi retire more or less com- 
pletely. 
We have in abundance in our seas the 
Alcyonium digitatum, Ell., Coral. xxxii., which is divided 
into thick, short branches ; Alc. eaos., which has more slender 
branches of a fine red, &c. 
Linneus, and his successors, have united, on rather slender 
grounds, to the alcyonia, divers marine bodies of various tissue, 
but always without visible polypi. Such are 
