MALAYAN PORITES. 165 
162. Porites Philippines @5. (P. Philippina quinta.) (Pl. XXV. fig. 6; Pl. XXXYV. fig. 8.) 
[Philippines ; British Museum. } 
Description.—The corallum rises into large, solid, round-topped masses like inverted cones. 
The tops are wavy or slightly indented. The living layer extends only 3-4 cm. down the 
steep sides. 
The calicles are minute, about 0°75 mm., only slightly pitted. The walls, thin and 
zigzag, are rows of minute frosted granules, the tips of trabecule. In the angles and on the 
sloping sides they are often reticular, the network being granular, open, and delicate. The 
septa are very thin and delicate, and here and there rise to the surface, but most frequently 
the parts most visible are the septal granules, which rise either as granules or as short radiating 
plates and mostly distinct from the wall. Within this ring are the small frosted pali in a 
large open ring. The complete formula is frequently seen. The central tubercle is frequently 
flattened and thin. The interseptal loculi are large and open, and the whole intra-calicular 
skeleton appears scanty, at least at the surface, where it chiefly consists of well-spaced frosted 
granules. These surface granules at the sides of the stock may all be flattened and appear 
like the tips of lamellate plates, radial arrangements of them forming the walls. 
The vertical section shows a very dense arrangement of fine trabecule distinctly showing 
lamellate surfaces. The meshes are frequently like oval pores in a membrane. The colour 
of the unbleached coral is brown. 
There is one large incomplete stock ; it is a wedge-shaped mass split down longitudinally. 
Boring molluscs in the heart of the original stock from which it was broken seem to have 
prevented its growth from being regular and symmetrical. A great cavity with sloping sides 
opened on its top. 
There is no other Porites like it in the collection. 
a. Zool. Dept. 98. 4. 21. 1. 
163. Porites Philippines @6. (P. Philippina sexta.) (Pl. XXV. figs. 7, 8.) 
[ Zamboanga, coll. H.MLS. ‘Challenger’; British Museum. ] 
Syn. Porites explanata Quelch, Chall. Rep. xvi. (1886) p. 181, pl. xi. figs. 3, 3a. 
Deseription.—The corallum is small, thin, explanate, attached by the centre to the back of 
a Gastropod shell (Murex) on which it was carried about. Its edge is free for 1 cm. all round 
the margin, supported by epitheca, and sharp, but thickens rapidly to 1-1°5 mm. 
The calicles, though 1 mm. in diameter, are difficult to distinguish, being ill-defined as 
