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MR. H. N. MOSELEY ON THE 
EN. Entoderm. 
C. Canal cut transversely. 
Fig. 10. Portion of the superficial structures of Helioporci ccerulea as viewed in a thin 
vertical section. 
E. Ectoderm, consisting of elongate club-.shaped cells running out below 
into fine processes, which traverse the next succeeding layer (M) of 
homogeneous connective-tissue. At the bases of these cells are 
cells of similar structure but irregular form. Small nematocysts lie 
amongst the epithelial cells, and some of them (N) are shown in the 
deeper regions. At EN the wall of one of the tubular cavities of 
the coenenchym is seen in section at its edge, showing its three layers 
and the residue of animal matter (P) left by parts of its calcareous 
wall after decalcification. 
Between EN and the section of the wall of the canal (V') a narrow 
strip of the inner surface of the tubular cavity is viewed from its 
surface aspect. 
E. Epithelial layer. 
M. Layer of homogeneous connective-tissue. 
N. Nematocysts. 
C. Connective-tissue cells. 
V. Canal of superficial system. 
V'. Canal of deep system. 
EN. Entodermic cells. 
D. Layer of connective-tissue cells. 
P. Besidue of tissue after decalcification of a portion of the wall of a 
ccenenchy m-tub e. 
Fig. 11. Section vertical to the surface of the corallum of Ileliopora ccerulea , showing 
the structure of the hard tissue. 
A. Former calicle-cavity shut off from A' the recent calicle of the 
tabula, C. 
The tube-cavities on either side have similar tabulae developed in them. 
In some of the tubes their walls are shown as cut parallel to their surfaces, 
in other places the cut edges of the walls only are seen. 
The tabulae being applied against the already formed insides of the 
calicles and tubes as a later formation, the line of the old wall of the 
calicle can always be traced up for some distance past the level of the 
tabula, which appears as the bottom of a second tube fitted within the first. 
The fibres forming the walls of the tubes &c. are inclined upwards and 
outwards at a uniform angle from the vertical axes. 
A. Former; A', recent calicular cavity. 
C. Tabulee. 
