REPORT ON CORALS—DEEP-SEA MADREPORARIA. 153 
bending in towards them for the purpose at points somewhat further outwards; the 
quinary unite with the quaternary at a point still further distant, a condition thus 
exists which is like that in Deléocyathus and some Stephanophyllias. The disposition 
of the septa is remarkably uniform in all the systems; the columella is composed of 
contorted finely fascicular matter, it is large and low, flat surfaced, and oval in superficial 
outline. 
A mutilated specimen of what is apparently the young of the same species was 
obtained on another occasion with the soft parts attached. The disc at the margin 
of the calicle between the exsert septa was of a dark madder colour, and the same colour 
was extended on the membrane, stretching thence over the base to the region where the 
costal spines commence. Beyond this region the outer wall of the corallum was bare and 
not invested by living tissue, The remainder of the disc was of a pale bluish tint with a 
zone of intensely dark madder colour round the mouth. The young corallum is thinner 
in texture, and flatter, and with the septa little exsert. 
Extreme diameters of the calicles 47°5 mm. and 30 mm. respectively. Extreme 
breadth between the exsert tips of the septa, 57°5 mm. and 36 mm. Vertical height of 
the larger specimen to the margin of the calicle, 47°5 mm.; to the summits of the highest 
septa, 21°5 mm. 
One large perfect specimen dredged at Station 120, off Pernambuco, Brazil. 675 
fathoms. 
Mutilated young specimen. Station 78, off the Azores. 1009 fathoms. 
Stephanotrochus discoides, Moseley (PI. IL, fig. 2, 2a, 2b, 2c). 
Ceratotrochus discoides, Moseley, Proc. Roy. Soc., 1876, p. 554. 
The corallam is white and is saucer-shaped, but much flatter than in Stephanotrochus 
diademe ; there is a short pedicle and small scar of attachment. The primary and second- 
ary costee only are prominent, and bear each four or five short spines; the primary and 
secondary septa only are exsert, and these do not rise high above the margin of the calicle. 
There are six systems, and only four cycles. The septa of the fourth cycle being only 
partially developed in many of the systems, only two instead of four quaternaries being 
present in most of the systems, and these being those lying between the primary and 
tertiary septa. These quaternary septa are bent towards the tertiaries to fuse with them. 
The free borders of the septa are nearly straight, showing only an extremely slight indenta- 
tion indicative of the pahform lobe seen in Stephanotrochus diadema. All the septa 
except the quaternaries run straight towards the centre of the calicle. Their inner ends 
are thickened and dilated, and, fusing together with the addition of some diffuse cementing 
calcareous matter, form a sort of columella, the surface of which is excavated in the very 
centre of the calicle by a well marked pit. 
From the denseness of its calcareous tissue and its general appearance, this Coral 
(ZOOL, CHALL, EXP,—PART vi1.—1880.) G 20 
