berrant groups, 429.

Abyssinia, plants of, 375.

Acclimatisation, 139.

Affinities:
of extinct species, 329.
of organic beings, 411.

Agassiz:
on Amblyopsis, 139.
on groups of species suddenly appearing, 302, 305.
on embryological succession, 338.
on the glacial period, 366.
on embryological characters, 418.
on the embryos of vertebrata, 439.
on parallelism of embryological development and geological succession,
449.

Algae of New Zealand, 376.

Alligators, males, fighting, 88.

Amblyopsis, blind fish, 139.

America, North:
productions allied to those of Europe, 371.
boulders and glaciers of, 373.
South, no modern formations on west coast, 290.

Ammonites, sudden extinction of, 321.

Anagallis, sterility of, 247.

Analogy of variations, 159.

Ancylus, 386.

Animals:
not domesticated from being variable, 17.
domestic, descended from several stocks, 19.
acclimatisation of, 141.
of Australia, 116.
with thicker fur in cold climates, 133.
blind, in caves, 137.
extinct, of Australia, 339.

Anomma, 240.

Antarctic islands, ancient flora of, 399.

Antirrhinum, 161.

Ants:
attending aphides, 211.
slave-making instinct, 219.

Ants, neuter, structure of, 236.

Aphides attended by ants, 211.

Aphis, development of, 442.

Apteryx, 182.

Arab horses, 35,

Aralo-Caspian Sea, 339.

Archiac, M. de, on the succession of species, 325.

Artichoke, Jerusalem, 142.

Ascension, plants of, 389.

Asclepias, pollen of, 193.

Asparagus, 359.

Aspicarpa, 417.

Asses, striped, 163.

Ateuchus, 135,

Audubon:
on habits of frigate-bird, 185.
on variation in birds'-nests, 212,
on heron eating seeds, 387.

Australia:
animals of, 116.
dogs of, 215.
extinct animals of, 339.
European plants in, 375.

Azara on flies destroying cattle, 72.

Azores, flora of, 363.

Babington, Mr., on British plants, 48.

Balancement of growth, 147.

Bamboo with hooks, 197.

Barberry, flowers of, 98.

Barrande, M.:
on Silurian colonies, 313.
on the succession of species, 325.
on parallelism of palaeozoic formations, 328.
on affinities of ancient species, 330.

Barriers, importance of, 347.

Batrachians on islands, 393.

Bats:
how structure acquired, 180.
distribut