402 



INDEX. 



NES 



Nests of birds continued. 



sand-martin, 302 



burrowing-puffin, 302 



woodpeckers, 303 



chaffinches, 304 



cassiques, 305 



tupuba, 305 



the Baltimore oriole, 305 



weaver-birds, 306 



bay a sparrows, 307 



social grosbeak, 308 



tailor-bird, 309 



tallegalla, or brush-turkey, 310 



sea-lark, 311 



cuckoo, 311 



Newton, Sir I., his discovery of the 

 universal law of gravitation, 4 



Nitrogen, as a constituent of our at- 

 mosphere, 16 



Noctiluca miliaris, 105 



Notonectidse, or boat-flies, their method 

 of motion, 200 



Nummulites, 103 



Nut-weevil, 219 



OCEAN, its immensity, 21 

 its past and future, 21 



blessings it gives us, 22 



its ebb and flood, 22 



causes of the tides, 23, 24 



their influence on the organic life of 



the seas, 23 



system of ocean-currents, 24, 25 

 - their importance, 25 



evidence of unity of design resulting 



from the intimate connection of 

 the phenomena of the seas and the 

 distant celestial bodies, 26 



submarine meadows of grass-wrack, 



55 



causes of the luminousness of the 



sea, 104, 148 



submarine gardens, 116 

 Octopoda, arms of the, 163 

 Ocypoda, or sand-crabs, legs of the, 



178 

 Oestri, or breeze-flies, their instincts, 



224 

 Onisci, or wood-lice, 177 



feet of the, 179 

 Onychotenthis, arms and tentacles of 



the, 161 

 Ophrydinse, 109 



Opossum, parental affection of the, 374 

 Orang-oetan, skull of the, 391 

 Oriole, Baltimore, nest of the, 305 

 Oscillatorise, the, 95 

 Ostracion, cuirass of the, 250 

 Ostrich, wings of the, 288 



its parental affection, 313 



PRO 



Ostrich continued. 



its artifices in deceiving its enemies, 



313 



Otter, formation of the, 320 

 Oxen, wild, of the llanos, their mode of 



defence, 369 

 Oxygen, its combustibility, 16 



its importance to animal life, 1 7 

 Oysters, 153 



PAGURI, habits of the, 187 

 Palm-trees, roots of, 57 



stems of, 66 



thorns of the Caryota horrida, 68 



Parasitic plants, 66, 67 

 Parrots, intelligence of, 314 

 Parrot-fish, dental apparatus of the, 



253 



Peccari, mode of defence of the, 369 

 Pelican, foot of the, 292 

 - bill of the, 295 

 Pelopseus, or dirt-dauber, its earthen 



cells, 226 



Pengolin, tail of the, 336 

 Penguin, wings of the, 288 

 Pennatulae, 120 

 Pentacrinites, 132 

 Perching birds, 293 



Phalangers, prehensile tails of the, 336 

 Phallus foetidus, its rapid growth, 51 

 Philodina roseola, 173 

 Pholades, 151 



their burrowing apparatus, 151 

 Phyllostomas, tongue of, 349 

 Pine, roots of the, 57, 58 

 Pistils of plants, 80 



Planetary system, the, 3 



Kepler's discovery of their motions, 4 



planetary perturbations, 4 

 Plantain, gigantic size of the stem and 



leaves of the, 72 

 Plants. See Vegetable Life. 

 Platypus, duck-billed, its masticatory 



organs, 340 



Podurinse, or spring-tails, 199 

 Poison-fangs of serpents, 277 

 Pollen of plants, 80 

 Polycystina, the, 105 

 Polyzoa, 143 



Porcupine, its means of defence, 368 

 Porliera hygrometrica, the, 75 

 Poulp, sucking disks of the, 162 

 Prairie-dogs, burrows of the, 362 

 Protococci, the, 94 



their still and motile cells, 95 



their mode of propagation, 95 

 Protophyta, 94 



Protozoa, microscopical, 101 



rhizopods and foraminifera, 101, 102 

 their geological importance, 10 



