148 MADREPORARIA. 
The section shows a loose reticulum in which neither trabecule nor horizontal elements 
are conspicuous ; where most regular, both are equally developed with large rounded meshes. 
The colour is a bright yellowish-brown. 
This coral has all the characters of a ccenenchymatous Porites. (See Introduction, p. 15.) 
The single specimen is large, 11 cm. across, and is curiously associated with a Millepora of 
very much the same habit, only the surface and the processes are smoother. 
a. Zool. Dept. 92. 4. 5. 27. 
141, Porites North Australia (94. (P. Australie Borealis quarta.) 
(PL XXII. fig. 5; Pl. XXIV. fig. 3.) 
[Blackwood Shoal,* Arafura Sea, 10 fathoms ; British Museum.] 
Description.—The corallum forms irregular open tufts of short, thick (1°5 cm.), gnarled 
and rapidly tapering branches ; they tend to curve outwards and to fork irregularly, sometimes 
three points radiating from a centre. The living layer extends about 6 cm. down, and has 
a distinct creeping edge. 
The calicles are conspicuous, 1 mm. in diameter. The walls swell up into ramparts 
about 1 mm. high, sometimes thin, sharp, low ridges, at others taller and round-topped, either 
surrounding single calicles, which are thus sunk in deep pits, or enclosing two to three calicles 
in a wavy bent trough; young calicles appear on the swollen tips of the ramparts; the texture 
of the ramparts is closely reticular, and in contrast with the coarse flaky texture of the intra- 
calicular skeleton. The septa are broad flat flakes with finely pointed edges, and showing no 
very marked radial symmetry, but are often curled and bent up, showing lower layers of flakes, 
which seem to compose the bulk of the intra-calicular skeleton ; granules, as the tips of 
trabecule, are rare. Only here and there are the pali developed as a small ring of large 
granules rising apparently upon the innermost lobes of the flat septa. The section of a branch 
shows the horizontal elements alone conspicuous; trabecule, even in the sections of the 
ramparts, are only just traceable. 
.The colour of the unbleached stock is a pinkish or reddish-brown terra-cotta. 
‘There are two specimens which show striking variations: a is a complete branching stock 
(Pl. XXIV. fig. 3) with the characters described; it is 10 em. high, 4 em. of which is dead 
previous growth. 6 has a different growth-form, but it is only a fragment, the branches 
flattening and forking nearly all in one plane; the calicles are more densely crowded and 
the ramparts thinner and ragged ; the surface has a rougher look than in a; and, lastly, the 
colour is dark brown. This ought probably to have been described under a separate heading. 
In addition to these two stocks, united because the type of calicle is the same, and 
because both have the rampart formation, and both come from the same locality, are two 
*.9° 53'S., 129° 25' E, 
