rudiments of, 450.
Ornithorhynchus, 107, 416.
Ostrich:
not capable of flight, 134.
habit of laying eggs together, 218.
American, two species of, 349.
Otter, habits of, how acquired, 179.
Ouzel, water, 185.
Owen, Professor:
on birds not flying, 134.
on vegetative repetition, 149.
on variable length of arms in ourang-outang, 150.
on the swim-bladder of fishes, 191.
on electric organs, 192.
on fossil horse of La Plata, 319.
on relations of ruminants and pachyderms, 329.
on fossil birds of New Zealand, 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:
392