ALCYONID&S 247. 
the polypidom is squat, with thick spreading arms covered with 
lobiliform branches, the tubercular polypidoms of which are columnar 
and obtuse, the spicula green, and the tentacula of the polyps 
yellow. ads 
“On a cursory view,” says Dr. Johnston, “the polypidom of the 
three families embraced appear very dissimilar, and accordingly, by 
many recent authors, they have ‘been’ scattered over the ‘class, and 
placed widely asunder. The affinity between them, however, ‘is 
generally acknowledged, and had been distinctly perceived by some 
of the earliest zoophytologists. Thus Bohadsch found so much in’ 
common in the typical Pennatula and a species of Alcyonium, that’ 
he has not hesitated to describe them as members of the same genus; 
and, although the more systematic character of Pallas prevented 
him from falling into this error, if, error it can be called, he did not 
the less recognise the relationship between the genera or families. 
Pallas also tells us that his Verretillum cynomorium differs from the 
Alcyonium only in this, that the former is a movable and the latter 2 
fixed polypidom; and he saw with equal clearness the connection 
which exists between these .genera and the shrub-like Gorgonia. Of 
the Virgularia 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 freé; and of the Sea-pens generally, Ellis remarks 
that they are ‘a genus of zoophytes not far removed from the 
Gorgonia, on account of their polyp mouths, as well as having a bone 
in the inside and flesh without.’ ‘On the other hand, the ' Gorgonia 
seem,’ says Pallas, ‘with the exception of their horny skeleton, to'be: 
nearly similar in structure to the. genus A/cyonium, but as there are 
species of Gorgonia which are suberose 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 osculent species ‘excepting their external habits.’” 
“With most corallines,”. says Frédol, “the elementary individual,’ 
in spite of the adhesion established among them, possesses a vital 
energy all its own; it isin 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 
association consists of a non-adherent polyp, 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 ot 
being horny or calcareous—that is, completely inert—are fleshy, 
with contractile powers; that is to say, animated. Consequently, 
the polyp of the Pexnatula are less independent of each other than 
