somatic, [35].

Reproductive elements, potential immortality of, [9];

of Vertebrates and Plants, [74].

Reversion, [3], [91], [105].

Roux, on the principle of “struggle,” [139].

S.

Sea-anemones, regeneration in, [4].

Sexual apparatus of Invertebrates, Weismann on, [72], [74].

Sexual-cells and somatic-cells, [75-77], [81], [84].

[Sexual propagation], essential meaning of, [8], [11], [87];