286 
MADREPORARIA. 
a. Neither trabecular nor horizontal or concentric layers prominent. 
P. Java Sea 2. The skeleton a confused reticulum, tending to be smooth and 
flaky. 
P. Maldives 2. 
P. Mauritius 3 and 5, 
P. Amirantes 2. > See description in text and figures. 
P. Amirantes 3. 
P. Providence Islands 1, 
b. The trabecular layers are conspicuous, often with an extra wall trabecula (see B above), 
especially in the basal regions, where growth in thickness continues after the 
budding has ceased. 
P. Samoa 1, With surface as a mosaic of granules; extra wall trabecule 
mostly present. 
P. Tonga Islands S. The walls slightly raised and rounded, but gradually 
flattening as a smooth mosaic; an extra wall trabecula mostly present. 
P. Tonga Islands 9, With walls mostly flat and showing extra wall trabecule, 
P. Fiji Islands 1, Extva wall trabecule chiefly near the base, where the 
granules tend to be rectangular and echinulate. 
P. Ellice Islands 16. Extra wall trabeculi are present near the base. 
P. Solomon Islands 3. Extra wall trabecule ; wall a thin faint ridge over upper 
part of stocks. 
P. Solomon Islands 9. Extra wall trabecule very frequent in all parts. 
P. Great Barrier Reef 12. Extra trabecule chiefly round the basal parts; here 
and there the granules are expanding to form next horizontal layer, and the 
surface then looks hard, smooth and flaky. 
P. Great Barrier Reef 1S. The surface is here velvety from the small echinulate 
tips of the trabeculz ; there, more smooth and solid-looking as the next 
horizontal layer is being developed. 
P. North Australia 2. With extra trabecule to basal calicles ; the concentric 
elements appear conspicuously between the wall trabecule. 
P. North Australia 7, The intra-calicular skeleton is trabecular; the walls are 
delicately flaky, with scattered granules on their surfaces. 
P. Kokos Island 1. The walls are flaky, but the intra-calicular skeleton is 
trabecular. 
P. Maldives 3. With traces of extra trabecule. 
P. Diego Garcia 3. It is difficult to say whether trabecular or horizontal ele- 
ments are here best developed. The few last forms here given supply us 
with transitions between this and the next sub-division. 
c. The forms in which the horizontal or concentric layers are strikingly developed at the 
expense of the trabecular. 
P. Tonga Islands 10. The trabecular granules still large and conspicuous, but 
scattered. 
P. Great Barrier Reef 3. Somewhat confused skeleton, owing to irregularity of 
the flakes and the granules. 
P. Great Barrier Reef 11, With septa as long, conspicuous tongues. 
