242 MADREPORARIA. 
“ 
The ealicles round the edges are superficial, but in the raised central regions depressed or 
erater-like (1-1°5 mm. across). The walls are thick, granular and echinulate, and hardly 
distinguishable from the septa. Every part of the surface is covered with fine granules running 
out into sharp points. The granules which form the ring of pali (four to five) are especially 
large and prominent, and the ring is therefore very conspicuous. There is no visible columella. 
The colour is grey or yellow. It is found on old branches of coral, but not common. 
This is Dr. Klunzinger’s original description simply rearranged. He further adds that the 
coral, but for the presence of the wall, would greatly resemble a Psammocora. We can gather 
further important details from the photographs. (1) On the higher parts of the stock the wall 
is round-topped and swollen; (2) the radial symmetry is irregular; (3) the septa appear to 
meet and fuse; and (4) frequently only six large interseptal loculi are present. 
There is no specimen of this Porites in the National Collection. Its small size and the 
irregularity of its calicular skeleton suggest the possibility of its being merely a young stage 
of some larger form. But on the other hand its position on dead branches of other corals may 
indicate special adaptation to such a habit. 
254. Porites Red Sea 8. (P. Lrythrwee octava.) 
[Red Sea, coll. Botta; Paris Museum.] 
Syn. Porites alveolata Milne-Edwards and Haime, Les Coralliaires, iti. (1860) p. 178. 
? Porites alveolata Klunzinger, Korallthiere des Rothen Meeres, ii. (1879) p. 43, pl. v. fig. 20. 
I examined three specimens labelled P. alveolata in the Paris collection. They repre- 
sented two, in my judgment, distinet forms. Comparison with the original description led to 
the conclusion that the two specimens, Nos. Z 197 @ and 0, were those on which the 
description was based. This can now be amplified. 
Description.—The corallum is massive, sometimes with gibbous or lobed surface. The 
living layer extends very unevenly downwards, and is closely adherent. 
The calicles are very deep, from sub-circular to angular, about 1 mm. in diameter. The 
walls are straight and thin, often with median thread. The septa are visible near the edges 
as points and granules, but soon project as thin very ragged spikes and ridges; some send up 
isolated pali, others not, most of them losing themselves in a columellar tangle, which is loose 
and open at first, but gradually becomes more compact. The pali are only suggested, except in 
the shallower calicles down the sides, where they develop into typical rings in which the 
four lateral principals are large and conspicuous. The central fossa may be large and open. 
The two specimens have very different growth-forms, the one being a rounded mass with 
knobbed surface, and the other a smooth-topped mass like a tableland, the living layer on some 
sides of which creeps smoothly and steeply down for 14cm. The calicles on the top open in 
a loose, angular reticulum. 
