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PLATE I. 
TO ILLUSTRATE THE STRUCTURE OF CORALS. 
(See Introduction.) 
The calice of Bathycyathus Sowerbyi (after Milne-Edwards and Jules Haime). The projection of the coste externally 
and of the septa internally is shown ; the existence of a wall between the junctions of the septa and coste is evident. 
There is no columella. 
The coste running down the outside of the corallum of Yrochosmilia tuberosa (after Milne-Edwards and Jules 
Haime). 
A section of a corallite of Lophohelia anthophyllites, Ellis, showing the dense wall, with the projection inwards of the 
septa. There are no coste. From nature, magnified. 
A corallite of Canocyathus Adamsi, Duncan,? showing the dase, the body, and the calicular termination.. The base is 
rough, and was formerly strongly attached to a foreign substance; the body has a few aborted buds on it, and the 
upper extremity shows faint costz terminating in septa. 
A longitudinal section of Sphenotrochus intermedius’ (after Milne-Edwards and Jules Haime). The central styliform 
process is the columella; it arises from the base internally, and is joined to the septa by lateral processes. It is an 
“essential” columella. The septa are shown as broad plates, granulated and arched; they are attached externally to 
the wall. Outside the faint shading of the wall is the slight projection of one of the coste. This corallite is open 
from the calicular margin to the base. 
The calice of Placotrochus costatus, Duncan.4 The upper and free surface of a long columella is shown, also the same 
structures as in fig. 1. Magnified. 3 
The external surface of the same coral, showing the irregular calicular margin, the strong coste, and the delicate peduncle 
of the base. 
Part of a calice of Placocyathus Moorei, Duncan,° showing the coste, septa, and part of a long columella, as in fig. 6; but 
there are pali on the ends of four of the septa. Magnified. 
The calice of Trochocyathus obesus® (after Milne-Edwards and Jules Haime), magnified. The larger septa are separated 
by three smaller, of which the middle one is the longest. There are twelve large septa, and every other one is a 
primary septum. The pali are before the primary, the secondary, and the tertiary septa. There are four cycles 
of septa. 
The calice of Discocyathus Eudesii’ (after Milne-Edwards and Jules Haime), magnified. The columella is lamellar, and 
the large pali are before the antepenultimate cycle (or the third). There are five cycles. 
Two corallites of Heliastraa endothecata,® Duncan, magnified. The cost seem to be united by transverse exothecal 
dissepiments, and the tooth of a small costa projects in the space formed by the dissepiments and the cost. 
Some ccenenchyma exists between the corallites. 
A longitudinal section of Conosmilia anomaia,? Duncan, magnified. The twisted processes forming the essential columella 
are seen, and one side of the lamina of a septum. This is granular, and is marked by a broken ridge, which once was 
continued to the next septum as a dissepiment. The wall is seen externally. 
A section of a corallite of Calamophyllia Stokesi (after Milne-Edwards and Jules Haime), magnified. The formation of 
a rudimentary columella is shown, and the sections of oblique dissepiments between the septa and crossing the interseptal 
loculi are seen. 
A longitudinal section of the upper part of a corallum of Caryophyllia cyathus™ (after Milne-Edwards and Jules Haime), 
magnified. The wall is the external and structureless part, and it has no costz projecting from it. The lateral view of 
the septa shows them to be granular, arched above, and slightly exsert. The pali are attached to the inner margin of 
the septa and to the outer part of the columella, which is formed by many twisted processes. A line drawn from the 
top of opposite septa forms the upper limit of the calicular fossa, and whose base is the top of the columella centrally, 
and the top of the pali. There are no dissepiments. 
A longitudinal section of part of the corallum of Anéillia Lonsdaleia,!? Duncan, magnified. The thin wall gives off inter- 
nally many dissepiments, which are joined by their side to the septum. Externally, it is in contact with a few 
oblique exothecal dissepiments. The granulated structure crossed by the exotheca, and external to the wall, 
is a costa, and is seen to emerge into a septum superiorly. The septum is very exsert, is bilobate, dentate, and is 
marked by radiating ornamental ridges. The columella is dense. The endotheca is vesicular. 
A corallum of the genus Montlivaltia, showing the epitheca with circular rings. 
A diagram of the relation of the hard and soft parts of a coral. The parts shaded are the wall, the part of the sclerenchyma 
below the newest dissepiment, and the columella. All the rest is in contact with soft tissues. The mouth and tentacles 
are shown. 
A diagram of the hard parts of a coral. The living tissues only cover the portion above the topmost exothecal and 
endothecal dissepiments. The base is pedunculate, and embraces a foreign substance; the columella springs from the 
inside of the base, and is in contact laterally with the pali. The septa, wall, coste, endothecal and exothecal dissepi- 
ments, are shown, and the trace of an epitheca quite externally and inferiorly also. 
Corallites of a Sarcinula’ (after Milne-Edwards and Jules Haime), united by peritheca; the cost are rudimentary. 
1 ¢ Brit. Foss. Corals,’ tab. ii. 2 “ Corals of Maltese Miocene,” ‘Ann. Mag. Nat. Hist.,’ s. 3, vol. xv, pl. xi. 
3 «Brit. Foss. Corals,’ tab. i, fig. 5. 4 Duncan and Wall, Jamaica, ‘ Quart. Jour. Geol. Soc.,’ Feb., 1865. 
5 Duncan and Wall, op. cit. 6 ‘Ann. des Sciences Nat.,’ 3me série, “ Zool.,” tom. ix, pl. x, fig. 2. 7 Ibid., pl. ix, fig. 7. 
8 Duncan, ‘ Foss. Corals of West Indies,’ ‘ Quart. Jour. Geol. Soc.,’ Nov., 1863, vol. xix, p. xv. 
® Duncan, “ Foss. Corals of Australian Tertiaries,” * Ann. Mag. Nat. Hist.,’ Sept., 1865. 
10 « Brit. Foss. Corals,’ part iii. 1 ¢ Ann. des Sci. Nat.,’ ut supra, tom. ix, p. 85. 
12 * Foss. Corals of West Indies,’ part ii, pl. iii. 18 «Ann. des Sci. Nat.,’ ut supra, tom. x, pl. vi. 
