Serranus, hermaphroditism in.

Setina, noise produced by.

Sex, inheritance limited by.

Sexes, relative proportions of, in man; proportions of, sometimes influenced by selection; probable relation of the, in primeval man.

Sexual and natural selection, contrasted.

Sexual characters, effects of the loss of; limitation of.

Sexual characters, secondary; relations of polygamy to; transmitted through both sexes; gradation of, in birds.

Sexual differences in man.

Sexual selection, explanation of; influence of, on the colouring of Lepidoptera; objections to; action of, in mankind.

Sexual selection in spiders.