of a Fossil Alcyonium. 407 
merly been considered as distinct species, will not be thought 
wholly uninteresting. 
I am, &c. , 
Lzwzs, May 20, 1814. Gipron MANTELL. 
P.S. Many very illustrative specimens of the Alcyonium Cho- 
noides have been discovered since the date of the above, all of 
which tend to confirm the opinions I have advanced respecting 
it. Some of these fossils are so highly interesting as to merit par- 
ticular attention ; but thinking it preferable to describe them in 
a future communication, rather than extend this postscript to a 
great length, I will only briefly notice two horizontal sections of 
the inferior part of the stirp, which exhibit the muscular fibres 
disposed in undulating plice, and the tubuli arising from thence, 
and terminating on the surface of the ventricular cavity. These 
sections so entirely resemble the siliceous specimen represented 
at tab. xii. fig. 9. of Mr. Parkinson's Organic Remains, that I 
have no hesitation in stating my conviction, that its markings 
are also derived from a similar cause. It is highly gratifying to 
me to quote Mr. Parkinson's remarks on this fossil; for although 
the specimen was not sufficiently illustrative to point out the par- 
ticular species of Alcyonium from which it originated, yet with 
that discernment and accuracy which always distinguish his re- 
searches, he readily traced its alcyonic origin, and describes it as 
“ being disposed in deeply-indented folds, somewhat like the he- 
raldic nebule, and consequently must have possessed in an emi- 
nent degree the power of enlarging or diminishing the cavity 
which it formed, by extending and straightening, or contracting 
and corrugating the line in which it was placed."—Organic Re- 
mains, vol. ii. p. 145. T 
Sept. 28, 1815. G. M. 
XXXIII. De- 
