dependent on continuity of germ-plasm, [104], [168];
dependent on coalescence of nuclei, [178].
Hertwig, O., on fusion of nuclei, [174];
on the influence of gravity in segmentation, [177], [189];
on polar bodies, [340], [351];
on process of fertilization, [355].
Hesperornis, rudimentary wing of, [88].
Heterogeny, [325].
Heterogynis, [44].
Heteroplastides, [130], [131], [134], [139], [146], [153], [204].