136 DESCRIPTION OF CORALS. 
The lamellae could not be reduced to symmetrical groups within any single area, 
and considerable inequalities existed in adjacent tubes; but there was a ten- 
dency in the broader plates to converge and unite in pairs with an interme- 
diate narrower one, and sometimes two of the latter occurred and formed a 
similar inner junction. No case was observed of a tube having been wholly 
filled up towards its lower extremity, but many were noticed in which the 
spaces between the lamella were greatly narrowed, and a few in which they 
were partially obliterated. The intertubular substance varied in texture, the 
reticulation being sometimes open or coarse, but sometimes replaced by a 
nearly compact mass, and without any reference to position as respected the 
surface or relative age. In the fragment mentioned as having formed portion of 
a third large specimen, the intertubular composition, at the narrow extremity, was 
almost uniformly compact, faint concentric lines being the principal indications 
of structure. The microscopic canals which permeated the reticulated fibres or 
laminze could readily be detected by a Codrington lens (fig. 3 0) ; and they were 
very distinct on slightly weathered portions of the general surface. 
Many instances of additional polype-cavities produced on the side of pre- 
viously existing tubes or near their base were noticed. Those in the latter 
position were distinguished from adjacent fully-grown stars by the small num- 
ber of lamella as well as other signs of immaturity; and little doubt could 
be entertained of their having originated, as in Oculina pallens, in the mantle 
or common animal envelope. The additional side-cavities were also apparently 
produced in the substance of the animal matter which formed and thickened 
the walls of the older tube, but there were indications of a connexion between 
the base of the former and the interior of the latter. In all cases the lamell- 
plates were equally developed around the area; and the termination of the 
cavities was in the same plane with the surface. Instances of what might be 
considered as double tubes, resulting from two cavities developed so near each 
other as to intermingle structure, were likewise noticed, and without care they 
might be regarded as having resulted from a subdivisional process. Polype- 
receptacles formed in expansions over destroyed surfaces displayed characters 
strictly analogous with those mentioned in the account of a base-layer of Oc. 
raristella *. 
* On the surface of the Bracklesham molluscous remains and rolled flints, a stellated coral not un- 
frequently occurs either singly or grouped. At first it was conjectured to be the base of the fossil 
referred doubtfully to Dendrophyllia, but Mr. Dixon having obligingly forwarded to the describer 
