339.
on succession of types, 339.
on affinities of the dugong, 414.
on homologous organs, 435.
on the metamorphosis of cephalopods and spiders, 442.

Pacific Ocean, faunas of, 348.

Paley on no organ formed to give pain, 201.

Pallas on the fertility of the wild stocks of domestic animals, 253.

Paraguay, cattle destroyed by flies, 72.

Parasites, 217.

Partridge, dirt on feet, 362.

Parts:
greatly developed, variable, 150.
degrees of utility of, 201.

Parus major, 183.

Passiflora, 251.

Peaches in United States, 85.

Pear, grafts of, 261.

Pelargonium:
flowers of, 145.
sterility of, 251.

Pelvis of women, 144,

Peloria, 145.

Period, glacial, 365.

Petrels, habits of, 184.

Phasianus, fertility of hybrids, 253.

Pheasant, young, wild, 216.

Philippi on tertiary species in Sicily, 312.

Pictet, Professor:
on groups of species suddenly appearing, 302, 305.
on rate of organic change, 313.
on continuous succession of genera, 316.
on close alliance of fossils in consecutive formations, 335.
on embryological succession, 338.

Pierce, Mr., on varieties of wolves, 91.

Pigeons:
with feathered feet and skin between toes, 12.
breeds described, and origin of, 20.
breeds of, how produced, 39, 42.
tumbler, not being able to get out of egg, 87.
reverting to blue colour, 160.
instinct of tumbling, 214.
carriers, killed by hawks, 362.
young of, 445.

Pistil, rudimentary, 451.

Plants:
poisonous, not affecting certain coloured animals, 12.
selection applied to, 32.
gradual improvement of, 37.
not improved in barbarous countries, 38.
destroyed by insects, 67.
in midst of range, have to struggle with other plants, 77.
nectar of, 92,
fleshy, on sea-shores, 132.
fresh-water, distribution of, 386.
low in scale, widely distributed, 406.

Plumage, laws of change in sexes of birds, 89.

Plums in the United States, 85.

Pointer dog:
origin of, 35.
habits of, 213.

Poison not affecting certain coloured animals, 12.

Poison, similar effect of, on animals and plants, 484.

Pollen of fir-trees, 203,

Poole, Col., on striped hemionus, 163.

Potamogeton, 387.

Prestwich, Mr., on English and French eocene formations, 328.

Primrose, 49.
sterility of, 247.

Primula, varieties of, 4