a 
16 G. LINDSTRÖM, ACTINOLOGY OF THE ATL. OCEAN. 
third. Those of the first order are thick, their superior edge is narrow and much 
curved in a line of zigzag, the undulations of which continue on the lateral surface 
of the septal lamine. These are covered with small, sparse granules. These septa 
never reach the centrum of the calicle and their vertical or interior edge ends before 
they are hemmed in between the septa of the second order. Between each septum of 
the first order there are two septa of the second, which are more narrow "and not so 
high as the former. They continue with their innermost edge very low and finely 
crenulated towards the centre of the calicle, where those which are situated on each 
side of a primary septum unite and coalesce along their whole interior margin. Thus 
every septum of the first order when seen from above is enclosed within a V shaped figure 
formed by its neighbouring septa of the second order. 'The lateral surface of the last is 
also covered with short spines and granulations. The loculi between the septa are quite 
open and free till the bottom of the calicle (see woodcut fig. 1). But if a segment of the coral, 
consisting of a primary septum and its two cireumambient secondary ones is taken apart and 
longitudinal and transversal sections of it are made, it is soon perceived that the septa 
Transverse sections of the same segment taken at different heights, fig. 1 being the uppermost, close to the bottom of the caliele, 
fig. 5 the lowest. a Principal part of the septum, 6. stereoplasma, c. loophole in the outer wall, perforating the epitheca. In fig. 
5 there are decper layers of stereoplasma obliquely shaded, from which an isolated point stretches upwards. 
frequently unite by means of a kind of synapticula, which indeed are nothing else but 
the spines or granulations of the lateral surfaces, that have grown from each septum 
towards the others, thus forming a kind of lattice work. Being more sparse in the 
upper and interior parts of the loculi, these junctions in the lower parts and still more 
so in the vicinity of the exterior wall become so dense and so en- 
tangled that it sometimes is difficult to unravel what is the septum 
and what the uniting parts. In the close vicinity to the outer wall 
these synapticula assume a most regular arrangement and form, as 
it were, pairs of two synapticula, one on each side of a primary septum 
(fig. 7 and pl. III, fig. 34), those of the same longitudinal row separated 
from each other by little round loopholes. These openings are then the 
only traces left of the loculi, and give origin to those peculiar dots and 
ARE NS & holes, which are seen on the outside of the epitheca. There are dots when 
MaA OA eENG RE the lacun& are covered by the thin pellucid epitheca; there are holes 
ters as before. when this thin covering 1s worn away. The contrast between the 
irregularity of these synapticula in the interior and their regularity near the epitheca 
is indeed very striking. As may be seen above from the figures 2 & 4 the loculi are 
sometimes almost closed up with this solid endotheca, by means of which the three septa 
are firmly soldered together into one compact segment. 
