Sladen, on classification of Asteroidea, [460]
Sleeping-sickness, [120]
Snow, red, [125]
Solaster, [453], [455], [463];
fossil, [475];
S. endeca, [463];
S. papposus, [463]
Solasteridae, [453], [455], [458], [462], [466]
Solenocaulon, [350]
Sollas, I. B. J., on Sponges, [163] f.