1882. ] MR. S. 0. RIDLEY ON THE CORALLIIDE. 221 
Atlantic. The Amphihelie are found in the North Atlantic and 
Florida seas, besides off Madeira; but Cladocora debilis appears to 
be a local species. The Balanophyllia is new, and has no definite 
alliances. Ceratotrochus johnsoni is a remarkable form of a genus 
of very great distribution ; and Caryophyllia endothecata is so im- 
portant a coral that I shall venture to write a separate memoir 
about its bearings on classification. 
EXPLANATION OF PLATE VIII. 
Caryophyllia endothecata, p. 216, natural size. 
——, the calice, magnified, 
—— ——, interseptal loculi, magnified. 
, cost, magnified. 
. Ceratotrochus johnson, p. 217, natural size. 
, a second specimen, natural size. 
—— ——,, the calice, magnified. 
—— ——, the cost, magnified. 
. Balanophyllia brevis, p. 219, natural size. 
10. —— , magnified. 
11. — , calice, magnified. 
12, —— ——, diagram of the septal arrangement. 
Fig. 
— 
$0 00 31 o> SUB G9 POT 
On the Arrangement of the Coralliide, with Descriptions 
of new or rare Species. By Stuart O. Rivtey, M.A., 
F.L.S., &c., Assistant in the Zoological Department, 
British Museum. (Communicated by Dr. Gintuer, 
V.P.Z.S.) 
[Received January 23, 1882, ] 
(Plate IX.) 
The smal] group of species which has been thought worthy of 
separation from the rest of its Alcyonarian allies as a distinct family 
under the name Corallide (more correctly Coralliide), is chiefly 
remarkable in its structural characters for possessing a continuous 
stony axis, covered by only a thin cortical layer of a softer spiculi- 
ferous material, into which the polypes are retractile. Its best claim 
to general notice lies in the fact that the Precious Coral of commerce 
(Corallium rubrum, Costa, rectius nobile, Pallas) is one of the only 
three species hitherto known to exist in the seas of the present time 
which have been included in it. The other two species are scarcely 
known, even to students of the group. Thus but one specimen of the 
species described by Dana (U.S. Expl. Exped., vol. vii. p. 641, pl. lx. 
fig. 1) under the name of Corallium secundum seems to have ever 
been described ; and but one specimen of the third species, described 
by the late Dr. Gray (P. Z.S. 1860, p. 393, Rad. pl. xviii.) under 
the name of Corallium (subsequently altered to Hemicorallium) 
Johnsoni, was obtained in the first instance, and I know of no other 
authentic specimen. The original specimen of this species, how- 
ever, is fortunately preserved in the national collection; that of 
