AUSTRALIAN PORITES, 129 
The calicles, 1 mm. in diameter and shallow, are of three kinds, very sharply distinguished 
from one another, On the level tops they open in a lamellate stroma, the walls being a re- 
ticulum, composed of thin, twisted, vertical flakes. The septa and the columellar tangle are also 
thin plates; there are no granules or echinule, and the calicle is flush with the surface. On 
the sides near the top, the walls are slightly raised, thin, very frosted or echinulate ridges, while 
the intra-calicular skeleton appears to consist entirely of rather crowded granules, the tips of so 
many echinulate rods rising up in the fossa, There is a ring of septal granules, sometimes 
joined on to the wall but mostly separate, and then a ring of pali, the pali being only dis- 
tinguishable in position and arrangement from the septal granules. They are in a complete 
formula, B, fig. 3, p. 19. The columellar tangle and the fusions of the septa are all deep down 
and obscure. The central tubercle is large, and flattened in the directive plane, and reaches 
nearly to the height of the pali. 
On the lower parts of the colony the walls flatten, thicken, and become solid, so that the 
septal granules appear upon their upper margins, and sometimes seem to send processes over 
them, giving an occasional appearance of irregular cross striation. 
The section shows a thick, very open axial network, as if consisting of filaments, while 
round this there is a compact layer of delicate radial trabecule. 
The colour of the unbleached coral is a light dull brown. 
This form is interesting, for it is an illustration in the genus of what, in Goniopora, I have 
called the expanding-sheaf method of growth, (See Introduction, p. 22.) The specimen 
consists of two tiers of columns. 
a, Zool. Dept. 92. 12. 1. 341. 
119. Porites Great Barrier Reef 4226. (P. Queenslandic seata et vicesima.) 
(Pl. XVI. figs. 8,9; Pl. XX. fig. 1.) 
[Thursday Island, coll. W. Saville-Kent and A. C. Haddon; British Museum. | 
Description.—The corallum forms rounded but flattened clusters of entangled branches, 
which radiate outwards from a small base of attachment, and fuse, soas to make an almost solid 
mass with openings into the interior. The round tips of the branches, which are from 1-1°5 cm. 
thick, project all round freely for varying lengths, 1-2 cm. The living layer extends some 
6 cm. down the branches round the periphery of the stock. 
The calicles on the upper parts of the stock are conspicuous and deep, especially on the tips 
of the branches, but in the valleys between these tips they are superficial, They are very 
variable in size, from 1-1-5 mm., and, where the walls are not surging up, angular. The walls 
of these angular calicles are mostly very thin and ragged, too irregularly frilled to show more 
than faint traces of a zigzag; here and there, however, they surge up into a loose filamentous 
reticulum ; it is this which causes the colony to rise into branches, and such calicles are always 
found on the tips of the branches. The septa are thin and irregular in shape and position ; the 
Ss 
