1898.] OOKALS OF THE SOUTH PACTEIC. 269 



regular and thinner than in the type, with their edges seldom 

 fused one to another ; in some of the cells 2-4 low pali can be 

 distinguished, appearing like mere thickenings at the edge of the 

 septa, but usually they are completely absent or quite indistin- 

 guishable. Columella generally absent or indistinct ; in some of 

 the calices strands of corallum occupying the bottom of the axial 

 fossa, which in others is very deep. 



. The type specimens (4) of this species were all obtained from a 

 pool in the reef near the island of Solkopi, to the east of Rotuma. 

 The variety was found on the reef quite near, and probably the 

 variations in its calices are correlated with its position. The types 

 of the species are two massive pieces broken off from the edges 

 of colonies and two quite young colonies. The latter have the 

 corallum less dense, walls thinner, septa seldom fused, pali often 

 more marked and regular, and columella sometimes quite small or 

 even indistinguishable. 



The specimen of the variety is rather more uneven and mamil- 

 late on the upper surface than the type. To it I have also 

 referred a small incrusting specimen, which differs in having the 

 septa more marked, regular, and broader, with both pali and 

 columella indistinct. 



The calices in all the specimens are in places arranged in lines, 

 the walls between neighbouring calices in the line being thinner 

 than between the calices of the one line and the next ; such lines 

 are rather irregular, but usually seem to run parallel to the 

 growing edge. The colour of the living colonies, both type and 

 variety, was the same, a very bright dark green. 



3. PoEiTES PURPUEBA, n. sp. (Plate XXIV. figs. 1 d, 3.) 



Corallum massive, uneven, irregularly monticulose, and niam- 

 illate, or with short columniform outgrowths, incrusting at the 

 base ; growing-edges 1-2 mm. thick, closely covered by the epitheca, 

 and often free for a few millimetres. 



Calices usually quite shallow, polygonal, about 2 mm. in 

 diameter on the tops of the mamillations and on the columni- 

 form outgrowths, but much smaller in the valleys between and 

 irregular in outline. Cell-walls sometimes quite thin on the 

 surface and angular in section, but more often, especially near the 

 base of the colony, quite blunt and as much as '5 mm. thick. 

 Upper edge of the v\'all covered with rough blunt spines, on the 

 thin walls a single row flattened at i-ight angles to the wall 

 between neighbouring calices and appearing continuous with the 

 septa within each ; the thick walls present an appearance as of 

 three rows of spines, a central higher one, and a row on each side, 

 but the latter is really a large tooth on the upper end of the septa, 

 projecting in the thin-walled calices almost at right angles to the 

 walls, but in the thick-walled almost vertically outward. Septa 12, 

 secondaries often fused with the primaries, usually thin with 

 rather rough sides, projecting for about a third its breadth into 



