120 MADREPORARIA. 
growing upon a somewhat similar oval ridge which had been overturned ; the otherwise smooth 
surface shows traces of cross furrows. | 
The calicles are small, under 1 mm., crowded, shallow, but distinctly depressed. The 
walls are variable and difficult to unravel, but show a thin, and inconspicuous, because often 
incomplete, zigzag line. From this the jagged and bent septa branch outwards to various 
distances, and slope downwards into the calicle. These septa may sometimes form an inner 
synapticular ring when wall and septa thicken; the fact that this inner ring is often complete 
makes it appear as if the wall were nearly solid and irregularly striated by very jagged or 
granulated septa. The thin-walled calicles occur on the top, where growth is most rapid ; those 
with thick walls, on the lower surfaces and especially at the sides. The sloping septa are 
irregular rows of coarse granules, so that the intra-calicular skeleton appears confused and 
broken up. The pali show large coarsely granular principals, but the ventral triplet has 
no fixed order, the three minute granules being variously arranged. The central tubercle is 
minute and deep down, the columellar tangle being quite obscure. 
In addition to the small specimen here described, there is what appears to be a second 
specimen of the same coral. The analysis of the calicles shows a similar structure, the 
differences being attributable to superficial variations of surface texture. Whereas in specimen 
a the skeleton is rather indefinitely coarsely granular, in 6 the skeleton is smoother but with 
sharp echinulations, and the granules are neatly star-like. 
Specimen 6 (Pl. XV. fig. 4) seems also to have started as a long oval ridge, which gave 
rise to others variously attached. Indeed, upon the dead part of the specimen when collected, 
the living layer formed a nearly spherical knob, 4 cm. in diameter, upon an irregularly 
prolonged end of a former ridge (Pl. XXI. fig. 6). The calicles which are growing fastest at 
the top of the knob have smoother and very incomplete skeletal elements, but elsewhere 
the calicles differ from those of specimen a almost entirely in the fact that the skeletal 
elements are neatly echinulate instead of being indefinitely granular. 
There is a young encrusting colony about 1:5 cm. long by about 1 cm. across, which is 
apparently a new growth of the same coral. 
a, A small ridge growing upon a previous 
ridge which had been overturned \ 
6. A globular knob, growing from an irregularly 
prolonged end of a ridge, upon which is 
a very young encrusting colony showing 
the beginning of the ridge formation. 
Zool. Dept. 92. 12. 1. 323. 
Zool. Dept. 92. 12. 1. 342. 
108. Porites Great Barrier Reef (4915. (P. Queenslandie quintadecima.) 
(GT XVe figs os Pl XOX, figs, 112!) 
[Rocky Island, coll. W. Saville-Kent; British Museum. ] 
Description.—The corallum rises as a thick ridge, the top of which swells into an irregular 
clump of uodules, too short to be called branching. The living layer is 4 cm. deep, and 
