AUSTRALIAN PORITES. 125 
113. Porites Great Barrier Reef (4920. (P. Queenslandie vicesima.) 
(Pl. XVI. fig. 1; Pl. XXI. fig. 10.) 
[Friday Island Passage, coll. 8. Pace; British Museum. ] 
Description.—The corallum forms a roughly oval mass, with wavy surface. It is 7 cm. 
long by 4°3 cm. in thickest diameter; the edges are inclined to be closely adherent, except 
when they cover over foreign bodies. [Mr. Pace informs me that it was attached by its lower 
end to the flexible stalk of a Zostra. | 
The calicles are small, 1 mm., inclined to be deep at the upper end of the stock, crowded 
and angular. The walls are everywhere simple, very thin, and with a tendency to be zigzag, 
only the trabecule are very incompletely joined together, so that the edge of the wall seen from 
above is frequently a row of frosted points variously joined by thin skeletal bars. Seen laterally, 
the walls are palisades of tapering bars very incompletely united. The septa are very thin, 
slightly granulated, and, seen from above, quite straight and symmetrical ; they project, however, 
at very different heights from the wall, a few from the extreme edge and the rest lower down. 
There are traces of rings of wall granules and septal granules, the upper edges of the septa 
being much interrupted. The pali themselves are not conspicuous, nor (owing to the porosities 
of the septa) very regular, for the granules at the points of fusion of the latter are frequently in- 
complete ; the formula consequently varies. The ring itself is small, and the central fossa deep, 
with a large tubercle deep down in its base. 
The colour of the unbleached stock is a bright red-brown. 
There is only one specimen, which Mr. Pace told me rocked about freely, being attached 
to the flexible stalk of an alga. In Vol. IV., cases of Goniopora were described, especially 
some in the Paris Basin, in which it was fairly clear that they had been attached to alge. 
This is the only case I have come across of a Porites attached to a weed. Ortmann described 
representatives of the genus from Dar-es-Salaam growing among weed, and apparently 
without any attachment. The phenomenon might be expected where the bottom consists 
of sand and weeds. 
In shape, colour and general character, the coral is not unlike P. New Hebrides 1 
(= P. parvistellata of Quelch). 
a. Zool. Dept. 1904. 10. 17. 39. 
114. Porites Great Barrier Reef (4221. (P. Queenslandie prima et vicesima.) (Pl. XVI. fig. 2.) 
[Thursday Island, coll. S. Pace; British Museum. ] 
Description—The corallum is explanate, thin, encrusting, with surface mostly smooth or 
slightly wavy. The edges are adherent and 0°5 mm. thick. The stock thickens to 5 mm, in 
a specimen nearly 4 cm. across. 
The calicles are very slightly depressed, almost superficial, small, about 1 mm., sub-cireular. 
