PLATE III. 



to illustrate the structure 0¥ corals. 

 Fig. 

 1, 2, and ". These illustrate the nature of synapticulae, from species of Micrahacia and Mycedmm. The 

 cross bars are not in the nature of dissepiments, and must not be considered to be the upper surfaces of 

 very oblique or nearly vertical dissepiments. 

 .3. Corallites of Alveopora (hedalaa} showing the regular perforations in the wall, constituting the species 



a " perforate" or porose coral. 

 -1. The perforate septa and walls of Litkarcea Websteri. Compare these cribriform septa with those of 



Sphenotrochus intermedins in Plate I, fig. 5. 

 .5. The wall, septa, and false columella of Alveopora fenestrata} 



6. The structure of the septa of the same coral seen longitudinally. They consist of a simple series of 

 projections, and do not form a continuous plate or lamina. 



8. The calice of Pocillopora erassoramosa,^ showing a horizontal dissepiment (a tabula) closing the 



calice below. It is marked by faint septa near the calicular margin ; the cceneuchyma external to 

 the calice is very dense and granular. 



9. A diagram of a longitudinal section of the same species. The tabulae with arched superior surfaces 



and the dense coenenchyma with its granules are shown. 



1 0. The tubuliform structures marked across by lines are corallites of Heliolites Murchisoni ; the tabulae 



represented by the lines are close ; the wall of the corallites is very slender, and there is much 

 cellular coenenchyma between the corallites. 



11. A longitudinal section of a tabulate coral, a Favosites. There is no ccenenchyma, but the walls are 



fused. 



12. Calices of Heliolites interstincta, magnified. The coenenchyma is cellular. 



13. Qi&\ices oi s.n Alveolites. 



14. Perforate walls of a i^(zwo«;Ye«. 



1.5. A calice of Stauria astrceceformis,* with three calicular buds. The quadriseptate arrangement is very 



evident. Magnified. 

 1 G. Longitudinal section of a corallite of the same species.* The dense walls, the endotheca forming 



cellular dissepiments externally and horizontal tabulje internally, and the septa, are shown. 



Magnified. 



1 7. The calice of Anisophyllum Agassizi,^ magnified, showing three large septa. 



18. The calice of Cyathaxonia cornu^ magnified. 



ly. The calice o{ Aulacophylluin mitratiim,^ magnified. 

 20. The calice of Ptycliophyllum expansum? 



^ ' Foss. Corals of West Indies,' pi. xiv. 



- ' Ann. des Sc. Nat.,' t. ix, pi. v. 3 < Yo^%\\ Corals of West Indies,' pt. ii, pi. 5. 



*~' Selected from 'Polyp. Foss. des Terr. Paleo.,' MM. Milne-Edwards et Jules Haime; they are 

 intended to illustrate the Introduction which will appear when the palaeozoic species are described. 



