Pore-rhomb, [597], [598]

Porifera, [163] f.;

definition, [180];

systematic position, [181]

—see also Sponges

Porites, [368] f., [373], [387], [388], [397]

Poritidae, [396]

Porocone, [81]

Porocyte, [186], [199], [231]

Porosphaera, [193], [282]