rtility of Rhododendron

Nodules, phosphatic, in azoic rocks

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
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