POLYNESIAN PORITES. 61 
In section the skeleton is light and very trabecular; judging from the depth of the 
colouring matter and from the tabul, the polyps penetrated about 3-5 mm. below the level of 
the walls on the upper, but much less on the lower surface. 
This Porites is quite unlike any other of the Fiji forms in habit, yet close examination 
shows it to belong to the group. Its median wall-ridge, the regular structure of the wall- 
reticulum, the structure for which Mr. Gardiner has suggested the term “trimurate,” the 
sinking of the ridge to the level of the general surface, and lastly the growth-form, are all 
characters exemplified by Fiji forms, but still more by those from Ellice Island. 
The specimen is only a broken portion of an edge, with no other indication as to its true 
shape or position in life than can be gathered from the characters of the calicles. Two of the 
calicle modifications are given in the figures. Fig. 7 shows the calicles of the expanding edges, 
where growth is rapid and the skeletal elements are smooth and flaky, and the reticulum is 
fluent. On the upper surface the skeleton is more regular and rigid and with frosted granules, 
while on the lower surface (fig. 8) the granules and the wall-flakes are swollen enormously, 
and the calicles but just recognisable. 
a. Zool. Dept. 1905. 19. 1. 11. 
38. Porites Fiji Islands 2423, (P. Fidjiensis tertia et vicesima.) (PI. IV. fig. 9.) 
[Rotumah, coll. J. S. Gardiner; British Museum. | 
Syn. Porites ? cribripora (Dana) Gardiner, Proc. Zool. Soc. (1898) p. 276. 
Description.—The corallum is small, thin and encrusting, about 1 mm. thick, and with 
irregularly wavy or wrinkled surface. 
The calicles are very small, under 1 mm., and, when not drawn out of shape, nearly 
circular ; they are shallow, but have very conspicuous walls, which are thick only in com- 
parison with the diameter of the calicles, They seem to be built of thin, smooth, horizontal 
flakes which slope downward on each side into the fossa, and along the tops of the flakes are 
flattened, frosted or ragged granules, which are mostly arranged as thin septal strie running 
radially, but not symmetrically so, over the walls, and round the edges of the stock out to the 
rim of the epitheca. The septa are ragged tongues of the wall flakes: the uppermost run but a 
short way, the second tier carries the pali, and below these again flakes, with a few pores, run 
right across the calicle. The radial symmetry is not marked, though the pali tend to show 
irregularly the formula D, fig. 3 (p.19). A central tubercle, short and stout, rises from the flakes 
which form the base of the fossa. The interseptal loculi are very irregular and inconspicuous. 
The marked flaky texture of this stock convinces me that it is not an early encrusting 
stage of some other growth-form, but that this is its normal form, Mr. Gardiner, in spite of 
the temptation arising from the similarity in general habit, rightly hesitated to class this with 
his group “ewilis,” one of which, viz. that next described, is also from this locality. Both have 
flaky walls, but in this specimen alone are they smooth and flat, in the next they rise up to 
form a light flaky reticulum. 
A small prominence on the surface of the colony is due to the rising up of a worm-tube, 
which is encrusted by the coral. 
a. Zool. Dept. 1905. 1. 19. 12. 
