270 MB. J. S. GARDINER OW THE PERFORATE [Apr. 5, 



the cell. Pctli usually 5-7, opposite and fused to the edges of the 

 septa, sometimes quite thin and styliform, but generally thick with 

 rugged sides ; their summits usually level with that of the wall 

 between the calices. Deeper in the cell septa and pali joined by 

 a ring of corallum, from which arise 3 or 4 strands to meet in the 

 centre of the calice, where the columella projects as a distinct thin 

 style with its summit in the thick-walled calices little below those 

 of the paH. 



In section the corallum is seen to be composed of very coarse 

 elements disposed in a very regular cross palisade arrangement. 



Funafuti ; lagoon shoals. 



There are three specimens of this species — one a mamillated 

 mass about 6 cm. high by 7 cm. broad, the second a column-like 

 outgrowth, covered on the sides with mamillations, 11 cm. high 

 by 6 cm. in diameter at the base, while the third is a mass inter- 

 mediate in form between these two. The colour of the living 

 colony with the polyps expanded is a dark purple, that of the 

 cleaned corallum light brown. 



The species is very abundant at Funafuti, and resembles in 

 some respects P. columaaris Kluuzinger, but I nowhere saw any- 

 thing approaching the long columniform outgrowths which are 

 described for that species. 



4. PoRiTES TRiMURATA, n. sp. (Plate XXIV. figs. 1 e, 4.) 



Corallum massive, uneven, slightly monticulose, incrusting at 

 the base, but in the larger colonies M^ith no free growing-edge ; 

 commonly flat table-topped, with a broad central pedicle and 

 edges about 7 mm. thick, covered with living calices which extend 

 for about 2 cm. on the lower side. 



Calices polygonal, moderately deep, about 1*5 mm. in diameter, 

 or 6 in 1 cm., smaller in the depressions. Cell-walls very thin, 

 regular, dense, and with few perforations, covered on the upper 

 surface with thick, rough, slightly flattened spines, which corre- 

 spond in position to the septa in the calices on each side. 

 Septa 12, appearing on the walls •4--5 mm. below their upper 

 edges and projecting into the calices for about a quai-ter their 

 breadth, usually rather thick with bluntly spinulous summits and 

 rough sides ; inner edges seldom fused with one another, thickened, 

 rough, very slightly projecting, apparently due to the fusion with 

 the pali, which would then vary in number from 6 to 12. Inside 

 the calice, between the thin wall proper and the point where the 

 septa may be seen distinctly arising, the wall is covered with low, 

 broad, rough spines, which in some parts form a distinct ring 

 within the calice, arising inside the true cell-wall from apparently 

 another wall, which is closely connected to it by the elements of 

 the corallum. On the undersides of the table-formed colonies the 

 calices present the same characters, but the pali are more distinct 

 and only lie opposite the primary septa, with which they are fused 

 below. The septal edges and pali are joined below by a ring of 

 corallum, from which usually 6 elements arise, fusing in the centre 



