in the Madreporide. 289 
so, cylindrical, except the terminal branches, which tend to 
curve outwards and taper gradually to points ; diameter, main 
axes 6-7 millim., intermediate and terminal branches about 
4 millim., greatest length between bifurcations of main 
branches about 30 millim., terminal twigs 25 millim. long. 
Calicles arranged more or less definitely, for the most part 
in series which follow approximately the longitudinal axis 
of the stem and branches, the calicles of one series alterna- 
ting with those of the adjacent series ; series about 2 millim. 
apart, calicles about 2 to 2°5 millim. apart in the series. 
Calicles forming, everywhere but on the tips of the branches, 
low rounded elevations, by the gradual rising of the surface 
towards their inferior margins to a height of :25 to -7 millim., 
and occasionally by the similar but very slight elevation of 
their superior margins. Calicles orbicular, looking upwards ; 
orifice of adult calicles 5 to *7 millim. in diameter ; on the 
tips of the branches they open on the level of the surface of 
the corallum, are more or less imperfectly defined from the 
surrounding loose coenenchyma, and measure about 25 to 
‘4 millim. in diameter. Septa trabecular, consisting of ver- 
tical series of horizontal pointed projections from the wall 
of the calicle, beginning just below its margin, distinct. 
Primaries about *25 millim. in length in full-grown calicles, 
comprising two main, opposite ones, variously placed (7. e. 
from parallel to the long axis to at an angle of 45° with the 
same), which converge towards the bottom of the calicle, 
where they meet and form a vertical plate ; the other prima- 
ries are slightly smaller and do not meet below. Secondaries 
varying from about half the diameter of primaries to mere 
points on the side of the calicle ; the secondary septum between 
the two lateral primaries is sometimes wanting. 
Corallum slightly vermiculate, always covered by minute 
points at surface (at apex looser, very porous) ; the outer one- 
quarter of diameter (except at apex, see fig. 5), formed of 
a denser tissue, in which the calcareous trabeculae exceed in 
diameter the spaces between them ; the central one-half of the 
diameter (viz. usually about 2 millim.), consisting of a loose 
tissue, in which the calcareous bars are only about half the 
diameter of the intervening spaces; the meshes of this tissue 
(as seen in transverse section of a branch) elongate towards 
margin, smaller and relatively shorter at centre. Apices of 
branches, to a distance of from 2-8 millim. from the ends (see 
fig. 5), formed of the looser axial coenenchyma, and carrying 
more or less rudimentary calicles, which are at least 1 millim, 
from all other calicles in the same longitudinal series. 
Hab. Keeling Islands, Indian Ocean ; deeper water inside 
reef. 
