186 MADREPORARIA. 
187. Porites Singapore (5. (P. Singaporensis quinta.) (Pl. XXVIII. figs. 5a, 5b; 
Pl. XXIX. fig. 4.) 
[West Singapore, coll. Raffles Museum ; British Museum. ] 
Description.—The corallum rises into irregular clusters of erect knobbed processes, 
6-7 em. high, rounded near the base, but greatly widened above, and with straight flat tops 
which all reach to about the same height. These processes divide up, and put out smaller 
flattened branchlets with narrow necks, and all bending up into the vertical. The explanate 
base creeps widely over the surface, the thick edge nowhere really free, but drooping, and even 
bending under; small upright processes are scattered round the central cluster. The surface 
is everywhere smooth. The spatulate tops of the processes are from 2—4 cm. greatest breadth, 
and from 1-1°5 em. thick. 
The calicles are superficial in faintly marked polygonal areas, 1*2-1°5 mm. across. The 
walls on the vertical sides consist of low, thin, median ridges, composed of single, more or less 
discontinuous rows of small frosted or branching granules. On each side is a horizontal shelf 
of flakes, sometimes separated from the median ridge by a row of small pores. On explanate 
surfaces the median ridge does not rise above the wall-level, and consists of a few threads, or 
even meshes of a very delicate filamentous reticulum which widens out at times in the angles. 
On the tops of the processes, the calicles open in a smooth reticulum, composed of filaments 
and flakes twisted in all directions (Pl. XXVIII. fig. 5a). 
The septa, in the calicles with wall ridges, appear at the surface as so many separate 
frosted granules (Pl. XXVIII. fig. 5b). The outermost ring—the septal granules proper— 
stand upon, and at the edge of, the wall shelf. Within this is the ring of pali, individual pali 
being sometimes joined high up with their corresponding septal granules. The complete palic 
formula is usually developed. On the explanate surface the septa are long and straight, with 
very echinulate, almost bushy, edges ; they taper away to fine points in the centre, without 
showing either septal granules or pali. The fosse are small, with a minute central tubercle. 
In the section there is the axial streaming of the flaky reticulum, surrounded by a thick 
layer of the radial trabecule, which are far apart and separated by large circular meshes. The 
colour seems to have been brown. 
This coral, in having a streaming axial layer, coming to the surfuce at the tips of columns, 
which it appears to shape, is like P. Singapore 2, 3, and 4. But its growth-form is quite 
peculiar. It has some faint resemblance to that of P. North Australia 1 (the S. dilatata of 
Briiggemann). Its calicles differ from those of all the other Singapore specimens. 
a. Zool. Dept. 93. 7. 22. 20. 
188. Porites Singapore (76. (P. Singaporensis sexta.) (Pl. XXVIIL. fig. 6; Pl. XXIX. fig. 5.) 
[Singapore, coll. 2 ; British Museum.] 
Description.—The corallum rises and swells above a narrow base into an irregular cluster 
of coxcomb-like ridges. Along the tops of the larger, older ridges smaller ones arise, 
