142 THE VOYAGE OF H.M.S. CHALLENGER, 
The calicle is circular in outline, the septa are only very slightly exsert. The septa 
in the larger specimens are arranged symmetrically in multiples of eight in three cycles, 
There are eight primary septa, eight secondary, and sixteen tertiary, of successively 
smaller size. Opposite the secondary septa are eight pali. In one small specimen there 
are either fourteen or fifteen primary and secondary septa, and either seven or eight pali. 
In another small one there are sixteen primary and secondary septa, but only seven pali, 
there being a gap in the circle of pali opposite one of the secondary septa; but in another, 
almost equally small, there are eight well-developed pali. On rubbing down the base of 
this specimen in order to expose the earliest formed septa, I found these rather irregular 
when first brought into view by the section, but as soon as cut into so far as to be 
distinctly marked, showing plainly as eight in number—nowhere as six: I could only 
afford to cut one specimen. AU the septa are thin and delicate lamine, with nearly 
smooth surfaces. They are remarkably sinuous throughout their extent, and especially 
so towards their inner margins. They arise from the inner wall of the calicle along 
sinuous lines, so that when a vertical section of the corallum is made, the septa exposed 
Diagram showing a vertical section of Caryophyllia rugosa. 
nearest the line of section are cut through at a succession of intervals at their pro- 
jecting folds, and hence the section shows a series of chambers, one above another, 
separated by sinuous transverse lines of coral substance. 
The columella is composed of small, sinuous, lamellar processes, which are nine in 
number in the largest specimen ; four, five, and three in the smaller ones respectively. 
This species is retained as a Caryophyllia, notwithstanding the octameral arrangement 
of its septa, because it 1s most evidently from its general appearance, peculiar colour, and 
file-lke external surface, closely allied to Caryophyllia lamellifera. It is distinguished from 
this latter species by its octameral arrangement, the peculiar sinuosity of its septa, and the 
smoothness of their surfaces, and also in the adult condition by its simple cylindrical form. 
Height of the largest specimen, 4mm. Breadth of the calicle, 4mm. Height of 
the smallest specimen 2mm. Breadth of the calicle 2 mm. 
Six specimens attached to small stones, 
