AUSTRALIAN PORITES. 157 
an irregular number of small rods, with frosted tips, rising up to the level of the walls. When 
these are rubbed off, the septa appear to be short, thick, and wedge-shaped. The pali are in 
the complete formula. The fossa is large, but ill-defined, and has a minute central tubercle. 
The calicles of this coral, of which there is only one fine specimen (hollowed out), are very 
difficult to describe. The delicate filamentous reticulum on the walls, and the tall, thin pal, 
seem to indicate rapid surface growth; only when this is rubbed off do the stouter elements 
appear. These latter are alone seen on the under sides of the stock. 
a. Zool. Dept. 94. 6. 16. 15. 
153. Porites North-West Australia 8. (P. Australie Occidentalis octava.) 
(Pl. XXIII. fig. 9; Pl. XXXV. fig. 5.) 
[Lacepede Islands, coll. W. Saville-Kent; British Museum. | 
Description.—The corallum is explanate and encrusting, with thin, sharp edges. The 
smooth, wavy upper surface rises into small mammillate processes. Older stocks may form 
mounds with tall clusters of similar processes and drooping explanate edges. These processes 
are about 8 mm. in diameter and 1 em. high. 
The calicles are small, 0°75 mm., and crowded. The walls are rather thick, and below 
the surface appear to be reticular and flaky; their tops are covered with irregularly scattered 
frosted granules. The septa are short and thick, rather deep down, and apparently without 
the septal granules between the pali and the granules of the wall. The pali form a con- 
spicuous ring of the usual five principals as frosted granules, sometimes seen united by a ring 
of tissue; seen sideways they are tall, stout, irregular rods, rising to the height of the walls. 
The fossa is very minute, and mostly very deep, without central tubercle. 
The vertical section shows a fairly regular rectangular network, the meshes being, however, 
irregular in shape ; the trabeculze and the horizontal elements are about equally developed ; 
here and there, the former may become the more pronounced. 
The unbleached coral is a pale fawn colour. 
There are three complete stocks, showing three stages of development. 
A young explanate colony (c), from 1°5 to 2 em. across, and showing a rising in the middle 
obviously due to a worm-tube. It is only 1 mm. thick, and the walls and the pali are much 
lower; the surface appears to be a much more solid and compact arrangement of large 
granules. 
The second specimen (0) is about 6 cm, in diameter, with a few scattered mammillate pro- 
cesses, and its expanding edges flat or turned up by coming into contact with foreign objects. 
The largest is a mound of fused mammillate processes, about 8 cm. across and 5-6 em. 
high, with edges hanging down here, and turned out horizontally there. 
The general characters of the coral are very like those of P. Great Barrier Reef 6 from 
Palm Island, the skeletal elements of which are, however, lighter and more delicate. 
(with ¢ upon it). Zool. Dept. 93. 11. 8. 17. 
b, Zoo). Dept. 93. 11. 8. 12 (part). 
