Oak, varieties of
Onites apelles
Orchids, fertilisation of --the development of their flowers --forms of
Orchis, pollen of
Organisation, tendency to advance
Organs of extreme perfection --electric, of fishes --of little importance --homologous --rudiments of, and nascent
Ornithorhynchus, mammae of
Ostrich not capable of flight --habit of laying eggs together --American, two species of
Otter, habits of, how acquired
Ouzel, water
Owen, Prof., on birds not flying --on vegetative repetition --on variability of unusually developed parts --on the eyes of fishes --on the swim-bladder of fishes --on fossil horse of La Plata --on generalised form --on relation of ruminants and pachyderms --on fossil birds of New Zealand --on succession of types --on affinities of the dugong --on homologous organs --on the metamorphosis of cephalopods
Pacific Ocean, faunas of
Pacini, on electric organs
Paley, on no organ formed to give pain
Pallas, on the fertility of the domesticated descendants of wild stocks
Palm with hooks
Papaver bracteatum
Paraguay, cattle destroyed by flies
Parasites
Partridge, with ball of dirt attached to foot
Parts greatly developed, variable
Parus major
Passiflora
Peaches in United States
Pear, grafts of
Pedicellariae
Pelargonium, flowers of --sterility of
Peloria
Pelvis of women
Period, glacial
Petrels, habits of
Phasianus, fertility of hybrids
Pheasant, young, wild
Pictet, Prof., on groups of species suddenly appearing --on rate of organic change --on continuous succession of genera --on close alliance of fossils in consecutive formations --on change in latest tertiary forms --on early transitional links
Pierce, Mr., on varieties of wolves
Pigeons with feathered feet and skin between toes --breeds described, and origin of --breeds of, how produced --tumbler, not being able to get out of egg --reverting to blue colour --instinct of tumbling --young of
Pigs, black, not affected by the paint-root --modified by want of exercise
Pistil, rudimentary
Plants, poisonous, not affecting certain coloured animals --selection, applied to --gradual improvement of --not improved in barbarous countries --dimorphic --destroyed by insects --in midst of range, have to struggle with other plants --nectar of --fleshy, on sea-shores --climbing --fresh-water, distribution of --low in scale, widely distributed
Pleuronectidae, their structure
Plumage, laws of change in sexes of birds
Plums in the United States
Pointer dog, origin of --habits of
Poison not affecting certain coloured animals
Poison, similar effect of, on animals and plants
Pollen of fir-trees --transported by various means
Pollinia, their development
Polyzoa, their avicularia
Poole, Col., on striped hemionus
Potemogeton
Pouchet, on the colours of flat-fish
Prestwich, Mr., on English and French eocene formations
Proctotrupes
Proteolepas
Proteus
Psychology, future progress of
Pyrgoma, found in the chalk