PLATE I. 



TO ILLUSTRATE THE STRUCTURE OF CORALS. 



(See Lttroductmi.) 



The calice of Balliycyathus Sowerbi/i' (after Milne-Edwards and Jules Haime). The projection of the cos/te externally 

 and of the s(v;/a internally is shown ; the existence of a wall between the junctions of the septa and costie is evident. 

 There is no columi'lla. 



The costie running down the outside of the coralluni of Trochosmilia tnberosa (after llilne-Edwards and Jules 

 Haime). 



\ section of a corallite of Lophohelia anthophyllites, Ellis, showing the dense tfatl, with the projection inwards of the 

 septa. There are no costiie. From nature, magnified. 



k corallite of Coenocyallms Jdamsi, Duncan,' showing the base, the boily, and the calicular termination. The base is 

 rou;;h, and was formerly strongly attached to a foreign substance; the body has a few aborted buds on it, and the 

 upper extremity shows faint costs terminating in septa. 



A longitudinal section of Sphemtrochm intermedins' (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 costse. This corallite is open 



from the calicular margin to the base. 



The calice of Placotroclms costatus, Duncan.'' The upper and free surface of a long columella is shown, also the same 

 structures as in fig. 1. Magnified. 



The external surface of the same coral, showing the irregular calicular margin, the strong costae, and the AeWciXe peduncle 

 of the base. 



Part of a calice of Placocyathus Moorei. Duncan," showing the costae, septa, and part of a long columella, as in fig. 6 ; but 

 there urepali on the ends of four of the septa. Magnified. 



The calice of Trochocyathus obesus^ (after Milne-Edwards and Jules Hainie), 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 

 prmiary 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 Seliaslrtea endothecata," Duncan, magnified. The costae seem to be united by transverse exotbecal 

 dissepiments, and the tooth of a small costa projects in the space formed by the dissepiments and the costie. 

 Some coenenchyma exists between the corallites. 



A longitudinal section of Conosmilia anomala,^ Duncan, magnified. Tlie twisted processes forming the essential columella 

 are seen, and one side of the lamina of a septum. This is granidar, 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 Stoiesi^" (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 costaj projectmg from it. The lateral view of 

 the septa shows them to be granular, arched above, and slightly exsert. The pah 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 tO|p of the pali. There are no dissepiments. 



A longitudinal section of part of the corallum of Antillia 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 exotbecal 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 Montlivallia, 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 exotbecal 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, costae, endothecal and exotbecal dissepi- 

 ments, are shown, and the trace of an epitheca quite externally and interiorly also. 



Corallites of a Sarcinula '•! (after Milne-Edwards and Jules Haime), united by peritheca ; the costae are rudimentary. 



' ' Brit. Foss. Corals,' t;il). ii. ^ " Corals of Maltese Miocene," 'Ann. Mag. Nat. Hist.,' s. 3, vol. xv, pi. xi. 



■' ' Brit. Foss. Corals,' tab. i, fig. 5. ■* Duncan and Wall, Jamaica. ' Quart. Jour. Geol. Soc.,' Fei) , 1SG5. 



^ Duncan and Wall, op. eit. " 'Ann. des Sciences Nat.,' 3me serie, " Zool.." torn, ix, pi. x, fig. 2. ' Ibid., pi. ix, fig. 7. 

 '* Duncan, " Foss. Corals of West Indies," ' Quart. Jour. Geol. Soc.,' Nov., ISli,'}, vol. xix, p. xv. 

 ^ Duncan, " Foss. Corals of Australian Tertiaries," ' Ann. Mag. Nat. Hist.,' Sept., 1865. 



'" ' Brit. Foss. Corals,' part ill. " ' Ann. des Sci. Nat.,' ut supra, tom. ix, p. 85. 



''' ' Foss. Corals of West Indies,' part ii, pi. iii. '■' ' Ann. des Sci. Nat.,' ut supra, tom. x, pi. vi. 



