Sand-urchin, [529]
Sanidaster (a modified euaster in which a slender rod-like axis bears spines at intervals along its length), [222]
Sapropelic Protozoa, [48]
Saprophyte, [33], [37], [90], [113], [119];
relation to brood-formation, [33]
Saprophytic, nutrition, [33], [37];
Sarasin, C. F. and P. B., on the madreporic vesicle and axial sinus of Echinoidea, [528];
on the relationships of the Echinothuriidae and Holothuroidea, [537]
Sarcocystis, [98];