POLYNESIAN PORITES. 69 
There is another specimen, ¢ (PI. V. fig. 9), with a different growth-form, but which may, 
as suggested by Mr. Gardiner, come under the same heading. 
The specimen is a fragment of a massive block, with rounded and apparently smooth 
surface. The calicles are of the same type as those of the last form, but the whole skeleton 
is lighter and more open. The wall-ridge shows a tendency for the trabecule, though here 
and there seen to be separate, to fuse together to form a smooth, solid membranous ridge raised 
above the surface. The peculiar flattened and non-fusing pali are again seen, but owing, 
perhaps, to the comparative smoothness of the thin septa, the aspect of the calicles is very 
different, for the ring of large open interseptal loculi make the calicles look like dark round 
spots, considerably larger than those on specimen a (ef. Pl. V. figs. 6, 9). The “trimurate” 
character is more visible than in a. I would account for the difference as due to the different 
growth-forms. The rounded mass was apparently growing rapidly at the top, hence the 
openness of the skeleton and the smoothness of its elements. The flat-topped specimen a 
was growing but slowly at the top, and the skeletal elements were thicker and more granular 
or echinulate. At the projecting edges, where growth was apparently rapid, we get a type 
of calicle more similar to that of this specimen. 
If this association of the specimens be correct, it would show that the table-topped 
growth-forms are accidental, that is,a@ may have reached the surface of the water, and its 
growth may have been solely lateral, c may have been sufficiently below that level, and have 
been still growing upwards. On the other hand, it is also clear that what is known as the 
“expanding sheaf formation” might also account for the form of any single table-topped 
specimen (cf. Introduction, p. 16). 
C. Zool. Dept. 1904. 10. 17. 27. 
45. Porites Ellice Islands q76, (P. LElliciana sexta.) (Pl. VI. figs. 1, 2.) 
[Funafuti (lagoon), coll. J. 8. Gardiner; British Museum. ] 
Syn. Porites umbellifera (partim) Gardiner, Proc. Zool. Soc. (1898) p. 271. 
Description.—The corallum appears to have been a flat-topped growth, with thin, sharp 
projecting edges, under which the colony was alive for 1:5 cm. The upper surface is irregu- 
larly humpy, rather than wavy (cf. Diagram fig. 8, Pl. XIII.). 
The calicles are all flush with the surface, about 1-3 mm. in diameter. The median ridge 
of the wall is thin, very perforated, hence sometimes discontinuous, and echinulate ; it appears 
as a thread not raised above the surface, and separated from the inner synapticular wall by a 
ring of irregular pores which do not correspond with the interseptal loculi ; but where the 
meet this ring there is frequently a large, frosted, sometimes radially flattened, granule. The 
septa are very thin, laterally roughened rather than echinulate, and typically arranged, The 
pali are frosted rods, and show chiefly formula C, fig. 3, p. 19, in a rather small ring; the five 
principals being large, mostly rounded and very frosted, the palus on the dorsal directive being 
small, A thin, flattened central tubercle rises to the level of the pali, and forms a central rod 
from which four or five strands radiate symmetrically to join a columellar ring beneath the pali. 
Owing to the thinness of the septa, the interseptal loculi and other spaces are large and open. 
On the under surface the walls are thick and covered with a delicate frosted reticulum. 
