150 MADREPORARIA. 
143. Porites North Australia «6. (P. Australie Borealis sexta.) 
(Pl XXIL fig. 7; Pl. XXIV. fig. 2.) 
[Blackwood Shoal,* 10 fathoms; British Museum. ] 
Description.—The corallum rises from a closely encrusting base into irregular strings of 
round or oval masses, which are bent about in all directions, sending out off-shoots, which 
fuse together without order or symmetry. The oval masses are quite small at the tips, 
5-6 mm. in diameter, those at the base being about 1-8 cm. The living layer is 7-8 em. deep. 
The calicles are superficial or only faintly pitted; with small central bosses in the bases 
of large polygonal areas, 1°75 mm. in diameter. The walls look broad to the naked eye, but 
consist of a low, thin, very frosted or delicately echinulate median ridge, within which are 
irregular rings of septal granules, usually separate from the walls, of different sizes and lengths, 
and frequently as echinulate, or even finely branching granules. Within these again are 
the pali, usually in a close ring, showing the formule B or F (fig. 3, p. 19), the principals 
being large and triangular, and also very echinulate, almost bushy. Beneath these granules 
the septa can be seen as broad, solid and wedge-shaped, with echinulate edges, and leaving 
only narrow slit-like interseptal loculi. A pin-hole fossa is visible to the naked eye, but is not 
very sharply defined because radiating off into the interseptal loculi, and with a minute central 
tubercle below the level of the pali. 
Neither element of the skeleton is well-defined in the section; the trabecule are the better 
developed. The colour of the unbleached coral is a kind of ash-grey with a faint tinge of green, 
and with a whitish bloom over the surface. 
This Porites is remarkable for its growth. Those most resembling it are given in 
Table III. The stock has been broken somewhat, the moniliform excrescences becoming 
easily detached. 
Ss 2 23 
Rect tcnementntarte } Zool. Dept. 92. 4. 5. 23. 
144. Porites North Australia (g)'7%. (P. Australie Borealis septima.) 
(Pl. XXII. fig. 8; Pl. XXIV. fig. 6.) 
[Evans Bank,f Arafura Sea, 15 fathoms; British Museum. | 
Description.—The corallum branches, irregularly dichotomously. The branches are about 
1°5 cm. thick, bent, and sub-cylindrical, but flattened where the forking or branching takes 
place ; the tips are swollen and slightly flattened, and fork in an irregular manner, one portion 
of the swollen knob growing faster and thicker (8-9 mm.) than the other, which eventually 
comes to project like a spur from the side of the thicker and more rapidly growing branchlet. 
The living layer is 7 em. deep, the lower edge creeping over the dead previous growth. 
* 9° 53'S,, 129° 25’ E. t 9° 5}'S., 129° 323’ E. 
