226 MR. S. O. RIDLEY ON THE CORALLIID&. (Feb. 7, 
several smaller angular tubercles which point outwards ; size 053 to 
7058 mm. long by °035 mm. broad (including the tubercles); shaft, 
excluding tubercles, about ‘02 mm. broad. 
Hab. Mauritius, 75 fathoms. 
This species is based on a single dry specimen very finely preserved, 
obtained recently by the British Museum from a collector in Mauri- 
tius, Mr. V. De Robillard, together with some remarkably fine 
specimens of species of Gorgoniide. Its chief larger measurements 
are:—Main diameter of common stem’ 11 mm.; largest branch— 
antero-posterior diameter at base 10 mm., lateral diameter 7 mm. ; 
at 50 mm. from origin the same diameters are 7 mm. and 5 mm, 
respectively. Maximum transverse breadth of the whole corallum 
135 mm., maximum height 105 mm. 
The species differs from all to which names have been hitherto 
assigned in the elaborateness and peculiarities of its method of 
branching, with the exception of a specimen which was assigned by 
Dr. Gray (P. Z. 8. 1867, p. 126) to his Hemicorallium johnson, 
and which then belonged to the Liverpool Free Museum. ‘This 
specimen, differing as it does from the typical example of that 
species in the collection of the British Museum in its slender and 
strongly arborescent habit, appears to me to be entirely distinct from 
Dr. Gray’s species, a fact which is apparently meant to be indicated 
by his subsequent statement (Cat. Lithophytes, p. 24) that the 
so-called animal of his figure is a fleshy Alcyonoid parasitic on a 
stony coral. 
The present species agrees in the mode of branching in one plane 
with C. secundum, Dana(U.S. Expl. Exped., Zoophytes (vii.), p. 641, 
pl. lx. fig. 1), and also in the fact that many of the polypes are 
borne on small lateral branchlets; but differs from it (judging by 
the description) in having polypes on the posterior as well as the 
anterior surface, as also in the very pale pinkish colour of the cortex 
(that of C. secundum being scarlet), and the pure white of the hard axis 
(that of C. secundum being white and red). The small points which 
project from the cortex in the lines of Dana’s striz are, perhaps, 
represented by the small dots represented in Dana’s enlarged figure 
of a polype with adjacent cortex; but these may just as well be pits 
as dots, according to the figure. Nothing is known of the spicules 
of C. secundum; but, as we have seen above, that species must be 
referred to the genus Pleurocorallium. Those of C. stylasteroides 
differ from those of the white variety of C. nobile only in their 
size, which is about one third less than that of the latter; but the 
excavations for the verruce (Plate IX. fig. 3), and the thinness of 
the cortex, are amply sufficient to prevent its being confounded with 
that form. The apparent anastomosis between some of the branches 
is due to fracture and subsequent adherence of the broken pieces 
to the remainder of the corallum, the reunited pieces having 
apparently contrived to live. 
With regard to the axial tubes of 1 mm. diameter, alluded to in 
my diagnosis in uncertainty as to their import, they may possibly 
1 Broken off from the actual base. 
