tarctic lands, 381, 399.
on the plants of the Galapagos, 391, 398.

Hooks:
on bamboos, 197.
to seeds on islands, 392.

Horner, Mr., on the antiquity of Egyptians, 18.

Horns, rudimentary, 454.

Horse, fossil, in La Plata, 318.

Horses:
destroyed by flies in La Plata, 72.
striped, 163.
proportions of, when young, 445.

Horticulturists, selection applied by, 32.

Huber on cells of bees, 230.

Huber, P.:
on reason blended with instinct, 208.
on habitual nature of instincts, 208.
on slave making ants, 219.
on Melipona domestica, 225.

Humble-bees, cells of, 225.

Hunter, J., on secondary sexual characters, 150.

Hutton, Captain, on crossed geese, 253.

Huxley, Professor:
on structure of hermaphrodites, 101.
on embryological succession, 338.
on homologous organs, 438.
on the development of aphis, 442.

Hybrids and mongrels compared, 272.

Hybridism, 245.

Hydra, structure of, 190.

Ibla, 148.

Icebergs transporting seeds, 363.

Increase, rate of, 63.

Individuals:
numbers favourable to selection, 102.
many, whether simultaneously created, 356.

Inheritance:
laws of, 12.
at corresponding ages, 14, 86.

Insects:
colour of, fitted for habitations, 84.
sea-side, colours of, 132.
blind, in caves, 138.
luminous, 193.
neuter, 236.

Instinct, 207.

Instincts, domestic, 213.

Intercrossing, advantages of, 96.

Islands, oceanic, 388.

Isolation favourable to selection, 104.

Japan, productions of, 372.

Java, plants of, 375.

Jones, Mr. J. M., on the birds of Bermuda, 391.

Jussieu on classification, 417.

Kentucky, caves of, 137.

Kerguelen-land, flora of, 381, 399.

Kidney-bean, acclimatisation of, 142.

Kidneys of birds, 144.

Kirby on tarsi deficient in beetles, 135.

Knight, Andrew, on cause of variation, 7.

Kolreuter:
on the barberry, 98.
on sterility of hybrids, 247.
on reciprocal crosses, 258.
on crossed varieties of nicotiana, 271.
on crossing male and hermaphrodite flowers, 451.

Lamarck on adaptive characters, 427.

Land-shells:
distribution of, 397.
of Madeira, naturalised, 402.

Languages, classification of, 422.

Lapse, great, of time, 282.

Larvae, 440.

Laurel, nectar secreted by the leaves, 92.

Laws of variation, 131.