at one time of the year than another, and in proportion
to a certain temperature of the air, like other fixt animals
; for inftance, oyfters, which we obferve at certain
feafons producing a new fhelly ftratum, or layer, next to
the flefli in the infide of their upper and under fhell :
indeed, in many of the Gorgonias their lèverai layers of
hard parts, or bone, are very like thofe of fhells both in
their confidence and polilhed fhining quality. This
is remarkable in the Gorgonia verticillata. See Tab. 2.
fig. 4. where there is a fmall trunk of its natural fize,
and the top of it magnified at fig. 5. to Ihew the fhell-
like difpofition of the laminæ.
As I have endeavoured to prove that there is no communication
between the circles in the bony part of the
Gorgonia, fo it is evident there is none between the laminæ
or layers of the oyfier-fhell ; becaufe we often find
them bored all over by fea infeâs, and yet if the inner-
moft lamina next to the filh is found, the animal is
found to be in perfedt health and vigorous,.as I have often
experienced.
But perhaps the formation of the bony part of the Gorgonia,
and the nature of the connection of the different
circles of laminæ, of which they are compofed, may be
more naturally and fatisfadtorily illuftrated by examining
the bony part of the Pennatulas, or Sea-Pens, a genus of
Zoophytes not far removed from the Gorgonias, on account
of their polype mouths, as well as having a hone in.
the infide, and flelh without. One of the chief differences
is, that as the Gorgonias are always fixt, there is a
necefiky, that in order to keep them firm in their places
they fhould be fpread out at the bafe, both in the bony as
well as flefhy parts ; whereas the Pennatula, or Sea-Pen,
which is made for fwimming about in the fea, has its
i bone
b on e fo rm e d fmall at the bafe, and the flefli thicker, yet
tapering to the end. The Pennatula Encrinus, which I
had defcribed fome years ago under the title of Plydra
ardlica, or Great Greenland Polype (fee Eflay on Corall.
tab. 37. and 'Phil. Tranf. Vol. 48. tab. 12. pag. 305.)
will illuftrate the nature of the bony part of thefe animals,
where at fig. PI. acrofs fe&ion of the bone magnified
reprefents the different lamina;, fhewing the manner
of their increafe in proportion to the growth of the animal
and the fquare form of the bone.
There is fomething amazing in the manner that the^
Gorgonias take to fix themfelves to rocks and other hard"
bodies in the fea, to be able to withftand the impetuofity
o f the waves. This wonderful contrivance o f Nature is
certainly inftindt in this low order of animals. How
pleafing it is to view the various turns and windings of the
beautiful, thin, fpread, fcarlet bafe, formed by the bone
and flefli of the Gorgonia pretiofa, or common Red
Coral.
In the Philofophical Tranfadtions, Vol. 50. tab. 34.
fig. 10. is the figure of a remarkable groupe of Red-Barnacles,
called the Tulip Barnacle, covered partly with the
bafe of a G. pretiofa, or Red Coral. This red appearance
of the Barnacles luggefted to me, when I wrote that
Memoir, that the fine red tint of the Coral might have
been communicated to the Barnacles, as they both grew
together. This rare fpecimen is in the curious cabinet o f
Dr. J. Fothergill, F. R. S.
Every good colledtion of Red Coral from the Mediterranean
is full of examples, where not only Barnacles
and Wormfhells, but even fmall branches o f the white
Madrepores are totally covered over with the bone or hard
part of the Red Coral.