210 MADREPORARIA. 
211. Porites Ceylon g915. (P. Ceylonica quintadecima.) 
[Ramesvaram sub-fossil reef,* coll. E. Thurston ; British Museum. | 
Description—The sub-fossilised corallum appears to have been massive. The single 
specimen is a small flake, 2 em. thick, showing a worn upper surface and a horizontal section. 
The calicles are 1 mm. across. The walls are reticular, the median parts flaky, but the 
flakes give place to filaments, so that immediately round the calicle the reticulum is a close 
tangle of threads; this runs as the intra-calicular skeleton across the calicle, greatly 
obscuring the radial symmetry. The short, thin, bent septa early meet a large reticular 
columellar tangle, in which again the horizontal flakes like those of the wall appear. The 
calicles are rendered visible chiefly by the rounded interseptal loculi being arranged in rings, 
otherwise the horizontal section would have been a close, evenly porous, flaky and filamentous 
reticulum. 
There is one other specimen from Ceylon with flaky walls arranged like this, viz. 
P. Ceylon 9 (Pl. XXXI. fig. 1), but the skeletal elements are more delicate and with serrated 
edges. In this case they are all perfectly smooth, but that might be due to a secondary 
corrosion of the finer points by the action of water on the dead coral. 
a. Zool. Dept. 1904. 10. 17. 58. 
212. Porites Ceylon @9)16. (P. Ceylonica sextadecima.) (Pl. XXXI. fig. 5.) 
[Galle, coll. Dr. Ondaatje; British Museum.] 
Syn. ‘‘ Porites punctata Linné” Ridley, Ann. and Mag. Nat. Hist. xi, (1883) p. 258. 
Description.—The corallum forms massive blocks, with smooth rounded surface ; complete 
form unknown. 
The calicles are small, slightly under 1 mm., round, slightly but sharply sunk. The walls 
are an open flaky reticulum, with regular round pores. The flakes are confined to the walls, 
and never invade the calicle as tongue-like septa. These latter are thin, smooth and thread- 
like seen from above; seen sideways they are laminate but with large interrupting pores. 
They all join a columellar ring, which is seldom quite complete, and sometimes surrounds an 
open, deep, circular fossa, or is filled up by a tangle. Round this fossa the interseptal loculi 
form a ring of large, round, very conspicuous holes. Very faint elevations on the columellar 
ring and where the septa meet are the only indications of pali, of which no traces whatever 
can be seen from above. 
The section shows a rather close system of trabecule, inclined to be lamellate. The 
horizontal elements are too irregular to be visible as such, being represented by portions of 
lamelle often separated by considerable intervals. 
* See last footnote. 
