;
in nature often accidental, 409-411;
does not exist in organic nature as an end _per se_, 410, 411.

Bees, co-operative instincts of, 268.

Beetles, wingless, 68-70;
on oceanic islands, 224, 226, 229, 232.

Bell, Dr., on natural theology, 412.

Bell-bird, 396-398.

_Bembidium_, 233.

Bermudas, 225-227.

Biology, ideas of method in, 1-9.

Birds, ovum of, 124;
embryology of, 151-155;
paleontology of, 163-165, 172, 173;
brain of, 194-197;
as carriers of seed, eggs, and small organisms, 217, 218;
distribution of, 224-240;
aesthetic sense of, 380-385;
courtship of, 380-385.

_Birgus latro_, 62-65.

Blood, colour of arterial, 409.

Boar, _see_ Pig.

_Bombus lapidarius_, 331.

Bower-birds, play-houses of, 381-383.

Boyd-Dawkins, on flattening of early human tibiae, 96.

Brain, palaeontology of, 194-197.

British Isles, _see_ Islands.

Broca, 363.

Bronn, 363.

Budding, _see_ Germination.

Burdon-Sanderson, Prof., on electric organ of skate, 366.

Butler, Bishop, on argument from ignorance, 41.

Butterflies, defensive colouring of, 321-329.

C.

Caesalpino, on classification, 24.

Calf, embryology of, 153.

Camel, foot of, 187-191.

Canadian stag, 196, 198, 199.

Canaries, portraits of, 303;
first mentioned by Gesner, 312, 313.

Cape de Verde Archipelagoes, fauna of, 228.

_Carcharias melanopterus_, 149.

Carruthers, on evolution, 436-442.

Caterpillars, colours and forms of, 319, 322-326.

Cattle, portraits of, 311.

Causation, natural, 402, 413, 414.

Caves, faunas of dark, 70-72.

Cell, physiological, and properties of the, 104-134.

_Cerura vinula_, 325, 326.

_Cervalces Americanus_, 196, 198, 199.

_Cervus dicrocerus_, _issiodorensis_, _matheronis_, _pardinensis_,
_Sedgwickii_, _tetraceros_, 168.

Chalmers, Dr., on natural theology, 412.

Chameleons, 317.

Characters, as adaptive, 273-276, 286-293, 349;
as specific, 274-276, 286-295;
as congenital and acquired, 274-276.

_Chasmorhynchus niveus_, and _C. tricarunculatus_, 396-398.

_Chelydra serpentina_, anterior limb of, 179-181.

Chick, embryology of, 153.

Chimpanzee, _see_ Apes.

Chlorophyll, 408.

_Chondracanthus cornutus_, 122.

Cirripedes, 430.

Classification, 23-49;
of organic nature by Genesis and Leviticus, 23;
artificial and natural, 24-26;
empirical rules of, 33-40;
Darwin on, 35, 36, 39,40;
form of, a nexus or tree, 29-32;
of organic