262 MADREPORARIA. 
D. Cenenchymatous Forms. 
The growth-forms of the group are difficult to define. Roughly speaking, it includes all 
those forms the walls of which are sufficiently well developed as to be able to rise irregularly 
into papille. These papillae run together to form ridges and ramparts round individual 
calicles. A provisional definition—to be tested by further research—may be suggested. The 
ccenenchymatous forms are those in which the calicles are so unevenly distributed that, 
between at least a large proportion of them, the walls are thick enough to show several 
intervening costal trabecule (cf. Introduction, p. 15). Such thickened walls may or may not 
rise up into mounds or papilla. For further details see Table IV. 
Encrusting forms :— 
P. Fiji Islands 5. With crumpled surface and irregular ramparts. 
P. China Sea 3. Thin, freely expanding, with rounded papille. 
P. China Sea 12. Enerusting, with smooth, low, conical ridges, usually wider than 
walls, and carrying calicles. 
P. Amirantes 1, Thin, explanate, with the wide walls smooth and flat. 
P. Red Sea G6. Encrusting, with smooth, conical mounds. 
Doubtful forms :— 
P. Ellice Islands 2. It is not clear whether the proliferation of the walls may not 
be due to the presence of worm-tubes. 
Encrusting forms, which in older stages seem to lose the explanate base and tower up 
in masses, columns, or branching processes :— 
P. Society Islands 2. Dense clusters of tall, thin, flattened stems ; sharp wall-ridges, 
with ragged edges. 
P. Society Islands 8. Thick clusters of very rough, angular, flame-like processes. 
P. Fiji Islands 9, A cluster of angular stems; calicles scattered. 
P. Fiji Islands 14. Rough columns. Cf. original figure (see Table IIT.). 
P. Fiji Islands 15. Rough columnar mass. Cf. original figure (see Table IIL.). 
P. Solomon Islands 4. Coxcomb-like processes, with long intervening mounds on 
the walls. 
. Caroline Islands 3. Rises into towering columns; ccenenchymatous ridges, often 
wider than walls, and with calicles opening on them. 
P. Great Barrier Reef 9. Erect columns ; tall, cenenchymatous ridges intervening. 
P. Great Barrier Reef 10, Erect, irregular fluted columns ; ridges wider than walls, 
and carrying calicles. 
P. Phillppines 2. Rough, columnar mass. Cf. Dana’s original figure. 
P. Ceylon 19. “Vike P. Society Islands 3.” 
P. Red Sea 4. “Erect lobes or columns.” 
Sy 
Branching :— 
P. North Australia 4. Erect stem, with spreading branches; compact rampart 
formation. 
P. China Sea 10, A tangle of stems, with circular ramparts. 
