FOOTNOTES

[8] Draper: Human Physiology, p. 288.

[9] Leuwenhoek: Select Works, ii. p. 210. His figures, however, are very incorrect.

[10] See Leydig: Ueber den Bau und die systematische Stellung der Räderthiere, in Siebold und Kölliker’s Zeitschrift, vi., and Ueber Hydatina Senta, in Müller’s Archiv: 1857.

[11] Pouchet: Hétérogénie, ou Traité de la Génération Spontanée, 1859, p. 453.

[12] The Tardigrade, or microscopic Sloth, belongs to the order of Arachnida, and is occasionally found in moss, stagnant ponds, &c. I have only met with four specimens in all my investigations, and they were all found in moss. Spallanzani described and figured it (very badly), and M. Doyère has given a fuller description in the Annales des Sciences, 2nd series, vols. xiv. xvii. and xviii.

[13] Davaine in Annales des Sciences Naturelles, 1858, x. p. 335.

[14] Spallanzani: Tracts on the Natural History of Animals and Vegetables: Translated by Dalyell, ii. p. 129.

[15] In some cases of monstrosity, these organs are transposed, the liver being on the left, and the pancreas on the right side. It was in allusion to a case of this kind, then occupying the attention of Paris, that Molière made his Médecin malgré Lui describe the heart as on the right side, the liver on the left; on the mistake being noticed, he replies: “Oui, autrefois; mais nous avons changé tout cela.

[16] The term zöoid was explained in our last.

[17] In the cuttlefish there is the commencement of an internal skeleton in the cartilage-plates protecting the brain.

[18] It is right to add, that there are serious doubts entertained respecting the claim of a star-fish to the possession of a nervous system at all; but the radiate structure is represented in the diagram; as it also is, very clearly, in a Sea-anemone.

[19] Protozoa, from proton, first, and zoon, animal.