Spinipora, [284], [286]

Spintharophora, [216], [217] f.

Spinulosa, [461], [462] f.

Spiral, of stalk and stalk-muscle in Vorticella, [156] f.;

ridge on tentacles of Suctoria, [160] f., [162]

Spiraster (a spire of one or more turns, produced on the outside into several spines), [222]

Spirillina, [59], [64]

Spirochaeta (= Treponema, [111]), [120] f.;

"S." zeemannii, [120] f.;

S. obermeieri, [121]