139 MADREPORARIA. 
The colour of the unbleached coral is dark grey-brown. The vertical section shows a loose 
irregular trabecular system with tabulz very near the surface, so that the living flesh penetrates 
but a short way (1°5 mm.) into the corallum. 
This last fact may be correlated with the depth of the open cup-like calicle. In forms 
in which the intra-calicular skeleton is flush with the surface, the living matter penetrates 
4-5 mm. 
There appear to be two specimens. The explanate colony is only a fragment, looking as 
if broken from the edge of a larger stock, The deep folding under its edge is an interesting 
point, and seems to show that the real method of growth is quite irregular, and that it may 
form explanate sheets which crumple and fold, or it may be piled up into mounds which by 
the folding under of the edges may build up nearly globular masses. This reasoning seems to 
justify me in grouping with this irregularly explanate stock a round stalked knob, with traces 
of explanate portions round the stalk. But the real similarity between the two lies in the 
calicles, which are built on exactly the same plan. In this stalked globular mass the walls 
at the top surge up a little more fully, and the filamentous reticulum is thicker and a little 
more delicate. 
The fig. 2 (Pl. XVII.) of the magnifications is from this globular form. 
a, An irregular explanate fragment. Zool. Dept. 97. 3. 9. 227. 
b. A globular mass. Zool. Dept. 97. 3. 9. 59. 
It is worth noting that the next form has calicles which are but variations on this same 
type. But what the real relationships between them are, we have no means of ascertaining. 
They may all be the same coral. 
122. Porites Great Barrier Reef 4929. (P. Queenslandie nona et vicesima.) 
(Pl. XVII. figs. 3, 4,5; Pl. XXI. fig. 21.) 
[Torres Strait,* coll. H.M.S. ‘ Alert,’ W. Saville-Kent, and A.C. Haddon; British Museum. | 
Description.—The corallum rises into a smooth, rounded nodule; if it settles upon a 
loose object, it soon falls over and becomes free; if on a fixed object, it gradually expands 
to form a thick, flat-topped, mushroom-shaped mass, which dies down on the top, while its 
pendent edges hang down round a thick stalk of attachment; the different growth-edges are 
closely adherent, never free. The surface seems unable to live for more than 1 cm. under 
projecting sides of the mass. 
The calicles are distinct depressions, but vary in size from slightly over to slightly under 
1 mm., although the variations in this respect appear greater than they really are because of 
the much greater variation in the thicknesses and slopes of the walls. These walls on each 
side of their middle ridges are built of the peripheral ends of the septa, joined by a zigzag 
* The specimen (h) collected during the voyage of H.MLS. ‘Alert’ is recorded as from the 
“N.E. Australia.” That (c) collected by Mr. Saville-Kent is labelled only “Great Barrier Reef.” 
All the rest are from Professor Haddon’s collection, and are labelled “ Torres Strait.” 
