299 MADREPORARIA. 
The calicles are small but distinct, under 1 mm., very uniform. The walls are thin, 
straight rows of granules near the tops, but thicken lower down into a reticulum, often without 
median ridge. The septa are thin, short, and descend symmetrically down the vertical walls, 
uniting in the principal pairs. The interseptal loculi form a neat ring of small deep holes 
round the extreme periphery of the calicle. The pali are not conspicuous, all the granules 
being uniformly small and ill-defined. The complete formula may be often seen. The fossa 
is deep, and the base filled by a large columellar tangle. The tubercle is often absent, but is 
sometimes large and flattened. 
There is one large bleached specimen towering 35 cm. high. The earlier stock seems 
to have rolled over, and from innumerable points new nodulated or moniliform stems have 
sprung. Stems formed out of strings of swellings are known in Porites (see P. Great Barrier 
Reef 3, Pl. XIX. fig. 1, and P. North Australia 6, Pl. XXIV. fig. 2). The septa and pali rise 
high in the calicles, and they look shallow, but the columellar tangle is deep down, and the 
ring of interseptal loculi show the calicle under the pocket-lens as deep and cylindrical. This 
cylindrical form of the calicle is one of the features of the coral. 
a. Zool. Dept. 83. 7. 27. 11. 
231. Porites Mauritius 5. (P. Mauritiensis quinta.) (Pl. XXXII. fig. 9; Pl. XXXIV. fig. 1.) 
[Mauritius ; British Museum. | 
Deseription.—The corallum is an unattached cluster of radiating processes with slightly 
swollen, rounded, or hammer-headed tips. When too large and heavy to roll about, the lower 
surface dies, and the upper living layer sends down creeping edges over the dead portion. 
The calicles are very variable, according to the irregularities of the surface. On any 
smooth part they may be large, 1°5 mm., polygonal, open, conspicuous, and varying in depth. 
Over most of the surface small groups of deep funnel-shaped calicles rise up as the starting 
point of new outgrowths. The walls are very irregular, mostly thin, open, fenestrated, but in 
the angles and elsewhere thickened as a fine filamentous reticulum. Such a reticulum is also 
formed at the tips of the processes, both of those growing up freely and of those on which the 
specimen rested. Young calicles open in the angles. The septa are thin, symmetrical, 
appearing well below the level of the top of the wall, and with septal granules well developed. 
The pali are small, not much bigger than the septal granules, but taller; present in complete 
formula B (fig. 3, p. 19). The fossa is large, round, shallow, and not very distinct. The tubercle 
is thin and flattened, and on a level with the pali. The interseptal loculi have no sharp 
outlines, owing to the fine frosting of the septa. 
The section shows a confused open reticulum with very obscure radial trabecule and thick 
axial meshwork. The colour is brown, 
There are two specimens, showing two interesting stages of growth. One (@) is quite 
young, small and straggling, of a light brown colour and with the calicles very uniform, 
polygonal, shallow funnel-shaped, with frequently wall-, as well as septal-granules, and with 
