58 MADREPORARIA. 
figured by Mr. Gardiner (I. c. pl. xxiv. fig. 2). The great majority show the usual twelve septa 
fused in the regular manner. The skeletal elements are hollowed out by analga. The colony 
shows well developed edges to the successive growth periods. 
a. Zool. Dept. 1905. 1. 19. 7. 
b. Zool. Dept. 1904. 10. 17. 18. 
Specimen c (the largest specimen of “P. viridis”) (Pl. IV. fig. 3). 
The corallum is massive, but while at one part the edge is folded under, at another it bends 
upwards, and creeps outwards like that of specimen ¢, The massive end is smooth except for 
one small patch of valley formation. The walls are of a much lighter reticulum than in a. 
The median ridge is less pronounced, and the septal flakes are seldom so broad ; they have 
frosted tips, and the lower ones fuse, and thereby produce the typical septal formula more 
often than in a. Minute frosted pali rise from these septal fusions, which are most marked 
in the shallowest calicles. That part of the stock where the edge is folded under is especially 
noteworthy ; the calicles are deep, with tall, thick, round-topped walls consisting entirely of a 
filamentous reticulum without any trace of radial symmetry. A similar kind of wall appeared 
in specimen a of Goniopora North-west Australia 6 (Vol. IV., p. 63, Pl. IV., fig. 6). 
The skeletal elements are hollowed out by a boring alga. The horizontal and trabecular 
elements are about equally well developed. 
cs Zool. Dept. 1904. 10. 17. 19. 
Specimen d (PI. IV. fig. 4). 
A small massive growth, with convoluted surface like a. The calicle walls are a light 
flaky reticulum, without sharp median ridge, except in the valleys. The wall-flakes frequently 
run out into thin narrow septa, and all stages of septal fusion can be seen with corresponding 
formation of pali. At the sides the calicles are shallower, and the septa more flaky, with a more 
complete ring of rather larger pali; the central tubercle is very minute. 
The skeletal elements of this specimen are hollowed out by an alga, here and there right 
up into the tips of the wall reticulum ; it is possible that the absence of the median ridge may 
be partly due to the friability thus caused, and consequent abrasion. 
d, Zool. Dept. 1905. 1. 19. 8. 
Specimen e. 
A small encrusting colony, freely following the irregularities of the substratum ; with very 
thin edges and crumpled surface. The calicles are slightly deeper, and the walls a much finer 
and closer reticulum than in the foregoing. A small patch, however, has calicles, exactly like 
those of specimen a, thus compelling us to unite forms which in other respects could have only 
been united by guesswork. The wall-reticulum is at times a tall, thick, round-topped, 
almost filamentous foam, like that found on specimen ¢c, where the colony is folding over. 
é. Zool. Dept. 1904. 10. 17. 20. 
