Fic. 
PLATE III. 
TO ILLUSTRATE THE STRUCTURE OF CORALS. 
1,2, and 7. These illustrate the nature of synapticulz, from species of Micrabacia and Mycedium. The 
or 
na 
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. 
Corallites of A/veopora dedalea,' showing the regular perforations in the wall, constituting the species 
a “‘ perforate” or porose coral. 
The perforate septa and walls of Litharea Websteri. Compare these cribriform septa with those of 
Sphenotrochus intermedius in Plate I, fig. 5. 
The wall, septa, and false columella of Alveopora fenestrata.? 
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. 
The calice of Pocillopora crassoramosa,® showing a horizontal dissepiment (a tabula) closing the 
calice below. It is marked by faint septa near the calicular margin ; the coenenchyma external to 
the calice is very dense and granular. 
A diagram of a longitudinal section of the same species. The tabule with arched superior surfaces 
and the dense ccenenchyma with its granules are shown. 
The tubuliform structures marked across by lines are corallites of Heliolites Murchisoni ; the tabule 
represented by the lines are close; the wall of the corallites is very slender, and there is much 
cellular ccenenchyma between the corallites. 
A longitudinal section of a tabulate coral, a Favosites. There is no ccenenchyma, but the walls are 
fused. 
Calices of Heliolites interstincta, magnified. The coenenchyma is cellular. 
Calices of an Alveolites. 
Perforate walls of a Favosites. 
A calice of Stauria astreeformis,* with three calicular buds. The quadriseptate arrangement is very 
evident. Magnified. 
Longitudinal section of a corallite of the same species.° The dense walls, the endotheca forming 
cellular dissepiments externally and horizontal tabule internally, and the septa, are shown. 
Magnified. 
The calice of Anisophyllum Agassizi,® magnified, showing three large septa. 
The calice of Cyathaxonia cornu,’ magnified. 
The calice of Aulacophyllum mitratum,s magnified. 
The calice of Ptychophyllum expansum.® 
1 «Foss. Corals of West Indies,’ pl. xiv. 
2 «Ann. des Sc. Nat.,’ t. ix, pl. v. 3 * Fossil Corals of West Indies,’ pt. 11, pl. 5. 
49 Selected from ‘Polyp. Foss. des Terr. Paléo.,” MM. Milne-Edwards et Jules Haime; they are 
intended to illustrate the Introduction which will appear when the paleeozoiec species are described. 
