Footnote 14: Professor Huxley’s Lectures. Footnote 15: M. Milne-Edwards. Footnote 16: Professor Huxley’s Lectures. Footnote 17: ‘Palæontology,’ by Professor Owen. Footnote 18: Prof. Owen. Footnote 19: Mr. Gosse. Footnote 20: ‘Lectures on Comparative Anatomy,’ by Professor Owen. Footnote 21: Described in ‘The Microscope,’ by Dr. Carpenter. Footnote 22: ‘Lectures on Comparative Anatomy,’ by Professor Owen. Footnote 23: ‘Lectures on Comparative Anatomy,’ by Professor Owen. Footnote 24: Dr. F. Müller, of Santa Caterina. Footnote 25: ‘Recherches sur quelques Animaux inférieurs de la Méditerranée,’ par C. Vogt: _Mémoires de l’Institut National Génevois_, tom. i. Footnote 26: Published in 1858, by the Ray Society. Footnote 27: ‘Lectures on Comparative Anatomy,’ by Professor Owen. Footnote 28: ‘Evenings at the Microscope,’ by P. H. Gosse, Esq. Footnote 29: ‘Observations on the Caryophyllia Smithii,’ by Mrs. Thynne, in the _Annals and Magazine of Natural History_. Footnote 30: ‘Histoire des Corallines,’ par Professeur Milne-Edwards. Footnote 31: ‘Histoire des Corallines,’ par Professeur Milne-Edwards. Footnote 32: According to the system of M. Milne-Edwards, who made the Annulosa a particular object of investigation. Footnote 33: Dr. Thomas Williams on ‘British Annelides,’ British Association, 1852. Footnote 34: ‘Comptes rendus,’ July 1864. Footnote 35: ‘Palæontology,’ by Professor Owen. Footnote 36: Messrs. Woodward and Barrett on the Synapta. Trans. of Zoological Society, London. Footnote 37: ‘The Microscope,’ by Dr. Carpenter. Footnote 38: Mr. C. Spence Bate. Footnote 39: ‘Histoire naturelle des Crustacés,’ par M. Milne-Edwards. Footnote 40: ‘Evenings at the Microscope,’ by Mr. Gosse. Footnote 41: Jeffrey’s ‘British Conchology.’ INDEX. A Abrothallus, organs of reproduction of, i. 307 Absorption of light and heat, i. 34 effects of, i. 35, 36 generally independent of colour, i. 36 Melloni’s investigations into the laws of, i. 38 Prof. Tyndall’s experiments, i. 38 amount of radiant heat absorbed by the perfumes of flowers and plants, i. 43-45 experiments showing radiation to be equal to absorption, i. 46 great absorption of olefiant gas, i. 47 absorptive power of aqueous vapour, i. 53 dynamic absorption, i. 49 absorption a phenomenon irrespective of aggregation, i. 53 absorption of invisible rays by solids, liquids, and gases, i. 65 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