148 
THE OCEAN WORLD. 
tells us that his Pennatula cynomorium differs from the Alcijonium 
only in this, that the former is a movable and the latter a fixed poly- 
pidom ; and he saw with equal clearness the connection which exists 
between these genera and the shrub-like Gorgonia. Of the Pennatula 
mirabilis he had doubts whether it was not rather a species of 
Gorgonia, until he perceived that the stem was attenuated at each end 
and free ; and of the Sea-pens generally, Ellis remarks that they are 
‘ a genus of zoophytes not far removed from the Gorgonias, on account 
of their polype mouths, as well as having a bone in the inside and flesh 
without.’ ‘ On the other hand, the Gorgonise seem,’ says Pallas, 1 with 
the exception of them homy skeleton, to be nearly similar in structure 
to the Alcyonia ; but as there are species of Gorgonia which are sube- 
rose internally, and almost of a uniform medullary consistence, even 
this mark of distinction fails to separate the tribes, and we have little 
left to guide us in arranging these esculent species excepting their 
external habits.’ ” 
“ With most polypiers,” says Fredol, “ the elementary individual, 
in spite of the adhesion established among them, possesses a vital 
energy all its own ; it is in some respects quite independent. They 
have each its own particular will, which it is difficult to mistake for 
a common will ; but it is not thus with the Pennatula. Their associa- 
tion consists of a non-adherent polypier, which moves — obscurely, it is 
true — but still it moves. To what does this lead ? To this : that the 
parts which they possess in common, in place of being homy or cal- 
careous — that is, completely inert — are fleshy, with contractile powers ; 
that is to say, animated. Consequently, the polypes of the Pennatula 
are less independent of each other than the coral polypes, which have 
a central, perhaps a sensible organ, common to all, which binds them 
to each other, giving a certain unity to their acts. The Coralline 
polypiers have no will ; the Pennatula have. 
