Absorption bands in the red and green parts of the solar spectrum, i. 131
Acalepha, the simple hydra a phase in the life of the, ii. 91
Acalephæ, Campanograde, characters of, ii. 103
Acalephæ, Ciliograde, characters of the, ii. 101 mode of reproduction of, ii. 103
Acalephæ, Physograde, characters of, ii. 107
Acanthometræ, structure and habitat of, ii. 19
Acetic acid, chemical combination forming, i. 97
Acetic fermentation, fungus producing, i. 288
Acetylene, chemical composition of, i. 128
Achlya prolifera, structure and reproduction of, i. 220
Acids, their affinity for alkalies, i. 96
Acineta, structure and mode of reproduction of, ii. 77, 78 food of, and mode of seizing it, ii. 78
Acrocarpi, characters of the group, i. 328
Acrocladia mamillata, spines of the, ii. 180, 181
Acrosticheæ, characters of the, i. 359, 360
Actinian polype, structure and mode of reproduction of, ii. 130, 131
Actinian zoophytes, characters of, ii. 130, 131 thread-cells, ii. 132 structure of, ii. 134-136
Actinism of star-light, i. 55 of moon-light, i. 55 of sun-light, i. 56
Actinocyclus undulatus, structure of, i. 199, 200
Actinophrys sol, structure and reproduction of, ii. 16-18 certain degree of instinct exhibited by, ii. 18 its enemy, the Amœba, ii. 18
Adiantieæ, characters of the groups, i. 358
Adiantum Capillus-Veneris, or maiden’s-hair fern, structure and habitat of, i. 359
Adriatic sea, Foraminifera in the ooze of the bed of the, ii. 51
Adularia, or moonstone, fluorescent property of, i. 66
Æthalium septicum, structure and habitat of, i. 270-272 Amœba-like motions of, i. 270 mode of reproduction of, i. 271
Affinity, chemical, of kind and of degree, i. 95 relation between chemical affinity and mechanical force, i. 98
Agaricus, the genus, i. 261, 263 structure of the, i. 263
Agaricus campestris, or common mushroom, i. 261 structure and mode of reproduction of, i. 261
Air, a non-conductor of electricity, i. 32 amount of force exerted by the sun’s light within the limits of the terrestrial atmosphere, i. 34 absorption of radiant heat by, i. 41 effect of the rays of the sun falling on the earth through pure dry air, i. 53 spectrum analysis of the component parts of the atmosphere, i. 139
Air-vessel of Nereocystis Lutkeana, i. 249, 250