Apis, see Bees.

Apus, [152], [324].

Ascaris, [133], [144];

fertilization of, [177];

nuclear division in ovum of, [188], [232], [360];

spermatogonia of, [220];

spermatogenesis of, [375].

Ascidians, length of life of, [57].

Atavism, [179].

Atrophy, of organs, [85], [86].