Ismailia, prophylaxis of malaria at, [106]
Isochela (a chela divisible by each of two planes into two equal parts, the two ends being equally developed), [222]
Isocrinus—see Pentacrinus
Isogamy, [33] f.;
of Rhizopoda, [56] f.;
of Stephanosphaera, [128]
—see also Syngamy
Isospores, [85];
of Radiolaria, [76];
of Collozoum inerme, [76]