AUSTRALIAN PORITES. 151 
The calicles faintly pit the surface, sub-circular, about 1 mm. in diameter. The walls are 
wide and built of horizontal very feathery flakes, which may be either smooth at the surface or 
covered with fine flattened feathery granules, the beginnings of the next layer of flakes. 
These feathery, finely echinulate or frosted granules give a velvety aspect to the surface. 
The septa are wedge-shaped extensions of the wall-flakes into the calicle, extensions which are 
regularly constricted so as to form a regular ring of septal granules, separated from the wall 
by anarrow circular trough. The paliare regular, and mostly appear in formula C (fig. 3, p. 19), 
that of the dorsal directive being small. A small columellar tubercle rises high in the centre 
of the fossa. The interseptal loculi are narrow and seem sometimes to run over the wall 
between the wall granules. 
In the section the tangential and radial (trabecular) elements are about equally developed, 
with only small intervening pores, so that the section seems compact. 
The branching of this coral is interesting. Cf. this description and figures with those of 
P. North Australia 1, of which it may be a variety. 
a. Zool. Dept. 92. 4. 5. 25. 
145. Porites North Australia (8. (P. Australie Borealis octava.) 
(Pi XXII. fis 9. Pl XT. fig: 4.) 
[Parry Shoal,* Arafura Sea, 12 fathoms; British Museum.] 
Description—The corallum rises into a thick, central stem, irregularly swollen, 12 cm. 
long and 3 cm. thick, and tapering rather rapidly. From the sides of this, thin, slightly tapering 
branches, 1-1°5 em. thick at the base, and forking at intervals of 2°5 cm., project at a wide 
angle, and usually slightly upwards. The edge of the living layer creeps over dead portions. 
The calicles are large, 1-1°5 mm., very shallow, almost obsolete, open, polygonal. The 
walls consist of crisp horizontal flakes, with a median ridge of irregular, vertical and ragged 
rods, the tips of which expand into smaller flakes, which form the next layer of the wall. 
This ridge rises slightly above the surface. The septa are short, wedge-shaped prolongations 
of these flakes, with crisp or frosted edges, with irregular granules scattered over them. The 
pali rise from constricted end-pieces of these tongue-like septa, and are tall but very irregular, 
so that no formula applies; they surround a large, rather shallow fossa with a floor of flakes, and 
a small central tubercle. The interseptal loculi are large, but not very symmetrical. 
In section the horizontal layer is compact, and alone conspicuous. The colour of the 
unbleached coral is a black-brown, 
This is one of the branching forms in which the horizontal elements are developed at the 
expense of the radial. 
a, Zool. Dept. 92. 4. 5. 26. 
* 11°9'S,, 129° 394’ E, 
