222 MR. S. 0. RIDLEY ON THE CORALLIIDE. [Feb. 7, 
C. secundum is no doubt in America, in company with the other 
specimens obtained at the same time by the United-States Exploring 
Expedition. The Red Coral (C. xodile) occurs in the Mediterranean, 
and among the islands (e. g. Cape-Verd Islands, see Wyville 
Thomson, Voy. ‘ Challenger,’ Atlantic, i. p. 76) lying off the N.W. 
coast of Africa; it occurs nowhere! else, so far as I have been able 
to discover. C. secundum is recorded with doubt as from the Sand- 
wich Islands; it was probably obtained in the Pacific Ocean at any 
rate; C. johnsoni was obtained from Madeira. In the present paper 
is described a fourth species, and one which is probably not new, 
belonging to this remarkable and beautiful family: the one was 
obtained from the island of Mauritius, and is now in the collection 
at the British Museum; the other is stated to come from Japan, and 
will shortly be incorporated with the same collection. 
Arrangement of the Family.—The only attempt which has been 
made at classifying the species is that of Dr. Gray in a Note read 
before this Society, and published in its ‘ Proceedings’ for 1867 
(p. 125), and somewhat amplified in ‘ Catalogue of Lithophytes or 
Stony Corals’ (1870), p. 22. Dr. Gray divided the family and the 
original single genus Corallium into 3 genera, based mainly ou the 
distribution of the “polypes” (meaning polype-cells, verruce of 
Verrill) on the branches, viz. :— 
(1) Corallium, with the verruce slightly elevated from the cortex 
and scattered on all sides of the branches (incl. C. nobile). 
(2) Pleurocorallium, branching in a single plane; the verruce 
slightly raised, confined to one surface, and mostly placed on small 
branches chiefly found near the edges of the main branches (incl. 
C. secundum, Dana). 
(3) Hemicorallium. The verruce prominent, all occurring on one 
side of the branches (incl. C. johnsont, Gray). 
With regard to this arrangment, it seems well to point out that 
the characters on which it is founded appeal entirely to the naked 
eye. In the allied members of the same group, the Alcyonaria, 
Prof. Kolliker (see ‘Icones Histiologicee’) and Verrill (see various 
papers in the Proc. Essex Institute, Trans. Connecticut Academy, 
American Journal of Science, &c.) have shown good reasons for 
the belief that the majority of those characters, such as colour, 
manner of branching, presence or absence of anastomosis between 
branches, to which alone those writers can appeal who do not 
make use of a microscope in their researches, must be regarded 
as usually of no more than secondary importance in the estimation 
of the mutual affinities of the different subdivisions and species of this 
group. From personal study I can testify to the truth of this principle 
in the case of the Melitheide, which are probably the nearest allies 
of this family. In them anastomosis of branches may be simply a 
varietal circumstance ; coloration of the internal parts is open to the 
same remark, and external coloration is far more frequently so; the 
manner of branching is much the same in all ; so that, for classifi- 
Tt is found fossil in the Upper Pliocene and Quaternary deposits of South 
Italy, cf. Seguenza, Atti Ac. Line, (3) Mem. sc. fis. mat. nat. iii. pp. 331, 373. 
