32 Prof. P. M. Duncan on the 
is a thin dissepimental looking circle at the junction of the 
coste and septa, in places raised higher than the septal ends. 
Original width 5 millim. 
The septa reach from the foreign body to which the coral 
is attached but a very slight distance upwards; there is no 
true basal structure. 'The axial space shows the stone at its 
base, and it is clear that the septal apparatus and its asso- 
ciated costal structures were the first parts of the skeleton. 
2. (Pl. V. fig. 11.) 
A young, flat, discoid corallum, upon the side of a Podoseris 
elongata. The base is nearly circular at its edge, and the 
coral then slopes very slightly upwards, being covered by 
coste, to the calicular margin. The calice is sunken close to 
its margin and the columella is raised above the level of the 
rest of the calice and is formed by the inner ends of the 
longest septa. } 
The calicular margin is broadly elliptical and is recognized 
easily in places, and elsewhere is produced by close synap- 
ticulee. 
The septa are narrower than the coste, and some are very 
much smaller, unequal, irregular, long, and wavy, others 
rudimentary ; close to the coste there are seventy-two, and 
eight reach the columella, or, rather, form it. Some septa 
crooked, most uniting, and some bifurcating, the junction may 
result either in a narrow ora thick septum. The coste are 
not so numerous as the septa, slope widely upon the support- 
ing body, are subequal to very unequal, usually nearly 
straight, projecting, but slightly rounded, or flat or swollen 
here and there, close to touching, some bifurcating, united by 
transverse or oblique synapticule; the narrow intercostal 
spaces correspond with interseptal spaces. 
Height about 2 millim. long diameter, 8 millim., short 
diameter of the calicular part 5 millim. and its long diameter 
6 millim. 
It is evident that the septa and coste spring from the sup- 
orting foreign body without any intervening basal structure. 
The septo-costal cyclical number is attained very soon after a 
moderate breadth has been reached. 
Remarks upon some Morphological Details. 
The septa of the species are solid, unilamellar, and are 
formed by spicules which pass from within the septa out- 
wards to their surface from definite centres or nodules. Often 
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