Spirochona, [138];

adoral wreath of, [138] n.;

bud-fission of, [147]

Spiroloculina, [59], [63]

Spirostomum, [137], [153] f.;

supposed nervous fibrils in, [143]

Spongelia, [225]

Spongelidae, [220]

Sponges (= Porifera), [163] f.;

spicules, [170], [171], [172], [177] f., [183], [184], [187] f., [198] f., [222], [224], [231] f., [232];