AUSTRALIAN PORITES. 121 
appears to be creeping over and closely encrusting the surface of some of the topmost nodules 
of an earlier growth. The whole stock is very dense and stony. 
The calicles appear as ill-defined but conspicuous indentations, irregular in size and 
distribution, shallow, sub-circular, but star-like when seen from above, about 1 mm. or more in 
diameter. The walls are thick, swollen, and round-topped, with a distinct tendency, which 
is pronounced in sheltered spots, to form a blunt median ridge, so as to make the calicular 
depressions funnel-shaped. They are built up of a confused and close tangle of flaky 
reticulum, and hence are without true granules, and appear smooth and solid. The septa are 
ragged and wavy, sometimes as flakes with echinulate or frosted edges. They usually meet in 
the typical manner. The fusion into four pairs is constant, and from the tips of the points 
of fusion knobs or swellings represent the principal pali, but they are often quite obscure. 
The triplet is less often seen. The six interseptal loculi, as irregular wavy slits, open into the 
central fossa, and descend deep and conspicuous round the confused columellar tangle, which 
slowly fills up the fossa. From it usually rises a small columellar tubercle. 
The section of the stock, which is heavy and tough, shows that the elements are very 
stout, with large pores between. There are great numbers of delicate tabule from 0°25 mm. 
to 0:3 mm. apart. 
The single specimen of this coral presents many variations of calicle structure: in the 
valleys and protected parts the calicles are visibly star-shaped owing to the depth and 
symmetry of those interseptal loculi which open into the fossa. On the tops and outer faces 
of the nodules, i.e. in the most exposed places, the reticular walls are so thick and dense, and 
the intra-calicular skeleton so irregular, that the calicles are only seen as slight depressions 
in a solid stony surface, and with very obscured radial symmetry. Elsewhere the calicle 
skeleton is very pronounced, but is remarkable in the feeble development of the pali. 
a. Zool. Dept. 92. 12. 1. 352. 
109. Porites Great Barrier Reef 4916, (P. Queenslandice sextadecima.) (Pl. XV. fig. 6; 
Well, NOsGL, (ates, @))) 
[Rocky Island, coll. W. Saville-Kent ; British Museum.] 
Description.—The corallum rises into a clump of nodules. The clump is about as broad 
as high, the nodules being small, rounded, compressed, and at the top of the stock rather flat- 
topped. On their surfaces, groups of calicles can be seen surging up to form fresh knobs. 
The living layer descends 4 cm., and the creeping edge, which is rather thick, is closely 
adherent. 
The calicles are small, shallow, but distinctly depressed, very irregular in size; the 
larger about 1 mm. in diameter, and sub-circular. The walls vary greatly in thickness, and 
they appear to consist of an open ragged mass of thin, angularly-bent threads. In thick walls 
these are arranged as a reticulum, but in thin walls only a few scattered threads appear. In 
all cases this top wall-structure, reticular or not, seems to rise from flakes obscured in the 
R 
