232 MR. S. 0. RIDLEY ON THE CORALLIIDA. [Feb. 7, 
Relation of the Coralliide to other Families. 
The opera-glass-shaped spicule of Hemicorallium resembles strongly 
some forms of the “‘ Blattkeule”’ (Kolliker), or foliar clavate spicule, 
which is found in so many species of the family Melitheide, and but 
unfrequently elsewhere (see Muricea, Eunicea), that I am led to 
believe that we have in it a hint as to the sequence of forms connecting 
that family with the Coralliide; and it seems to me that Pleuroco- 
rallium on the one hand, and Mopsel/la on the other, mark the 
points at which the chain of continuity between lhe families has been 
broken. It is true, all the Melitheide do not possess this form, or 
at any rate not in its typical shape ; but those which I believe to be 
the central forms of that family, viz. the genus Mopsella (Verrill, 
= Melitella and Mopsella, Gray), do show it well developed ; and it 
may probably be traced, though under strange modifications, in the 
genus Melitodes. On the other hand, the peculiar cylindrical form 
of the Coralliide appears to me to represent a highly specialized form 
of the fusiform or cylindrical spicule which is an almost universal 
constituent of the cortex of the Gorgoniide, and which occurs in a 
usually unspecialized form in the Melitheide also. 
With respect to the Isidide, their strongly calcified calcareous 
joints forcibly recall the hard tissue of the Coralliide, with which they 
are homologous; and all the spicules found in their cortex appear 
(see KGlliker, Icon. Histiol. p. 140, pl. xix. figs. 1-3) to be referable 
to a sexradiate form very closely resembling, except in its larger size, 
that of the red Pleurocorallium; the separation of the hard pieces 
of the axis by horny joints, however, perhaps puts the family at a 
greater distance from the Coralliide than the Melitheide, in which 
these joints are already calcified. These horny joints, coupled with 
the absence of any spicule resembling the Melithzeid ‘“ Blattkeule,” 
removes the family from the neighbourhood of the Melitheide ; and 
it probably represents a primitive offshoot from the same stem as 
that from which the genus Corallium s. str. has arisen. 
Fossil Species.—In addition to the forms described as C. pallidum 
and C. deckii, mentioned above under Corallium stylasteroides, and 
to C. nobile, also noticed above as recently recorded in the fossil 
state from the Italian tertiaries, it may be observed that Prof. P. M. 
Duncan notices, Geol. Journ. xxxi. p. 675, some fragmentary speci- 
mens from the Oligocene of Oawaru, New Zealand, and refers them 
to Corallium, without assigning specific names: some of these are 
said to possess frequently-branching furrows and ridges on their 
surface, much developed and very irregular in distribution; they 
appear to somewhat resemble parts of C. stylasteroides ; but no con- 
clusions as to specific affinity can safely be based upon them. 
As Corallium nobile has a white variety, and as Prof. Duncan 
states that he has found specimens of C. pallidum with a slight pink 
colour, and points out how slight are the differences between the 
species, I do not see how that species can be maintained as distinct 
from C. nobile, the colour, looser texture of corallum, and more 
minute strise being the only distinctive characters given by Michelin. 
Seguenza (/. c.) speaks of fossil specimens of C. nodile without the 
