Natural selection, its general principles, i. 2-14.

Nature, sense in which the term is employed, i. 6.

Naudin, supposed rules of transmission in crossing plants, ii. [68];

on the nature of hybrids, ii. [48]-[49];

essences of the species in hybrids, ii. [386], [401];

reversion of hybrids, ii. [36], [49]-[50];

reversion in flowers by stripes and blotches, ii. [37];

hybrids of Linaria vulgaris and purpurea, ii. [94];

pelorism in Linaria, ii. [58], [346];

crossing of peloric Linaria with the normal form, ii. [70];