Nototrema frog, with a pouch for young, 87. Nuthatch, a climber among perchers, 172. _Opossums_, 200; habits of, 198; why surviving in South America, 197–199: their relation to Australian marsupials, 198. Orangutan or mias, 252. Orca or grampus, a flesh-feeding whale, 325. Ornithorhynchus, _and its home_, 188; _bill and feet of_, 189; structure of the, 190; the lowest milk-giver, 191. Osprey, the sea-eagle, 177. Ostrich _at full speed_, 137; structure and habits of, 138. Otter, common, 301; _sea-_, 302. Owen, Prof., on a reptile like platypus, 190; on advantage of pouch to marsupials, 193. Owl, adapted for night-hunting, 176. Owl-monkeys, 246. Oystercatchers, wading birds, 148. Paddle-fins of mud-fish, 35, 38. _Paleotherium_, 209; one of the ancestors of tapirs and rhinoceroses, 213, 261. Pallas cited, 11. Pangolins, structure and habits of, 203. Paraguay, rheas of, 139. Parker, Prof. Kitchen, on evolution, 191; on origin of mammalia, 191. Parkyn, Mr., on baboons, 249. Parrots, using beak in climbing, 165. Partridges, ground-nesters, 156. Peccaries of South America, 263. Peewit or lapwing, 148. Pelican, perches on trees, 148. _Penguin, home of the_, 147; swimming wings of the, 146. Perch, climbing, 66. Perching birds, 168–173; aquatic bird among, 172; bird of prey among, 172; climbers among, 172; darters among, 172; ground-feeders among, 170. Petrel, home of the stormy, 145. _Phalanger, a flying_, 193, 195. Pheasants, ground-nesters, 156. Phosphorescent, fish, 47, 48; fluid, 50. Pigeons, beginners in nest-building, 160; crop of, 161; passenger, 162. Pike, 65. Pilot-fish accompanying shark, 52. Pipistrelle the common bat, 236. Plates, horny, in duck’s bill, 142; in bill of Ornithorhynchus, 188; in mouth of whale, 328; under the snake’s body, used in walking, 112. Platypus, 188; knob on nose of baby, 190. Plesiosaurus, 92; _figured_, 89. Plovers, wading birds, 148; dragging the wing, 151. Pocket-mice of North America, 215. Poison of snakes a concentration of a substance found in ordinary saliva, 119. Poisonous snakes, 117–121. Polar bear, walrus fighting the, 309. Polypterus or bichir, 33. _Porcupine_, 221; structure and habits of, 222; tree, 222. _Porpoise_, 323; good type of whales, 324. Pouch-bearers, see Marsupials. Pouched-rats, burrowing rodents, 226. Prairie-dogs, burrowing rodents, 225. Protective, colours, 347; smells in animals, 347. Proteus of Carniola caverns, 79. Protopterus of the Nile, 33. Protorosaurus earliest known reptile, 91. Ptarmigan, white plumage of, 157. Pterodactyls or flying reptiles, 93; _figured_, 89. Pterygotus and early fish, 37; _figured_, 20. Puff-birds of America, 168. Puffin Island, sea-birds of, 142.