142 
THE OCEAN WORLD. 
The stalk of the polypier is hollow in the centre, having a long 
slender bone-like substance, which is white, smooth, and square, but 
tapering at each extremity to a line point. The polypi, which are 
fleshy and white, are provided with eight long retractile tentacula, 
beautifully ciliated on their inner edge with two series of short pro- 
cesses strengthened with crystalline spicula. The mouth in the centre 
of the tentacula is somewhat angular, bounded by a white ligament, a 
process from which encircles the base of each tentaculum, which thus 
seems to issue from an aperture. The ova lie between the membranes 
of the pinnae ; they are globular, of a yellowish colour, and by a little 
pressure can be made to pass through the mouth. The polypi are 
distributed with more or less regularity in such a manner that one ot 
the extremities of the common axis is always naked : this part has been 
compared to the tubulous part of a feather. The stem, common to the 
colony, is a solid central axis, more or less developed, which is covered 
with a fleshy fibrous substance, susceptible of dilation and contraction. 
The Pennatulidm comprehend fhree genera ; namely, those with 
polypes on bipinnate wings, having — according to Dr. Johnston — 
I’olypidoms plumose, in Pennatula. 
Polypidoms virgate, or wand-shaped . . , Yirgularia. 
Polypes, unilateral and sessile ) n 
, . £ Pavonaria. 
Polypidom, linear-elongate , . . . . $ 
In the genus Pcnnatula, the polypes are disposed in transverse 
rows upon the outer and inner edge, in a series of prolongations in 
the form of a feather. These winged species of polypiers are somewhat 
scythe-shaped, well developed, and furnished with a great quantity of 
pointed spieulm, which are constituted of bundles at the base of the 
calyx. The space between the two rows of appendages is sometimes a 
tissue, sometimes scaly, sometimes granulous. Of the Pennatula five 
species are known, and all of them appear to he gifted with phos- 
phorescent properties. We may note among these species Pennatula 
spinosa (big. 01), which inhabits the Mediterranean, and takes it 9 
name from its colour ; Pennatula phosphor ea, which abound in most 
European seas, being found in great plenty, clinging to the fishermen’s 
lines round our own northern shores, more especially when they are 
baited with mussels. 
P. pliosphorea is of a reddish purple, the base of the smooth stalk 
pale ; the raches roughened with close-set papillae, and furrowed down 
