AUSTRALIAN PORITES. 137 
are echinulate. The pali rise nearly to the height of the wall, and vary greatly in size among 
themselves. The five principals and the dorsal directive are usually large and echinulate; the 
usual three ventrals are frequently very minute. 
A central tubercle may be found either well developed and high, or very small and deep 
down among the strands of the conspicuous tangle of the columella, or absent altogether, the 
fossa being deep and open. 
The colour of the unbleached coral is a greyish brown, the grey being due apparently to 
a kind of bloom from the echinulation of the elements (not, however, anywhere seen). The 
section shows a probably unique arrangement of trabecule. They are thin and very loose, 
but at very uneven distances apart, frequently with large rounded pores between. 
There are two specimens, both knobs built up by irregular incrustations ; several super- 
imposed colonies can be traced by their broken edges. In both are traces of other organisms 
distorting the coral, sponges (clione), worms, etc. The calicles vary so greatly that we have 
almost every gradation between the extreme shown in the figure, and the flaky kind which 
superficially reminds us of the calicles of P. Singapore 7. 
a. Pl. XXI. fig. 23. Zool. Dept. 92. 12. 1. 530. 
bo. Pl. XVII. fig. 8. Zool. Dept. 92. 12. 1. 549. 
A third specimen may, perhaps, be seen in P. Great Barrier Reef 39. The calicles 
resemble one another, and the fact that this last-named coral encrusts a long worm-tube is 
quite in keeping with the observation above made as to the infesting of this growth with 
foreign organisms. 
126. Porites Great Barrier Reef (4233, (P. Queenslandie tertia et tricesima.) (Pl. XVII. fig. 9.) 
[Great Barrier Reef, coll. W. Saville-Kent ; British Museum. ] 
Description.—The corallum appears to form an irregular rounded knob, with slightly wavy 
or indented surface. If the knob falls over, fresh incrustations or knobs appear on the sides. 
The edges of the colony are closely adherent. 
The calicles are shallow and small, mostly under 1 mm, in diameter. The walls vary in 
thickness according as they are on elevations or in depressions. There is a strong tendency to 
form a fine, sometimes incomplete, zigzag median ridge, which may be observed when a stout 
granular reticulum appears. The septa are regular, and have large septal granules, which in 
some lateral calicles may fuse just below the surface to form a stout inner wall within a thin, 
raised, very zigzag median ridge. 
The pali appear in formula E fig, 3, (p. 19), the four principals showing a trace of being 
V-shaped, and the ventral triplet forming a trident. The pali rise asa central boss, conspicuous 
to the naked eye. The central tubercle is a frosted granule, sometimes joined on as the handle 
of the trident. The granules are everywhere finely frosted. 
The colour of the unbleached coral is a light brown, The section is somewhat dense, and 
built of thick trabecule compactly arranged, 
