Falcons, length of life of, [11], [37].

Fiedler, on polar bodies in sponges, [217].

Flemming, on nuclear division, [187], [231], [359], [361].

Flourens, on length of life, [7].

Fol, on fusion of nuclei, [174], [189];

on origin of ova, [222];

on multiple impregnation, [236], [238], [382];

on polar bodies, [340], [351];

on process of fertilization, [355].

Formica sanguinea and fusca, length of life of, [51].