The Riddle of the Universe at the close of the nineteenth century

by Ernst Haeckel

[14] Cf. Max Verworn, Psychophysiologische Protisten-Studien, pp. 135, 140.

[15] E. Haeckel, “General Natural History of the Radiolaria”; 1887.

[16] Vide Natural History of Creation, E. Haeckel.

[17] Law of individual variation. Vide Natural History of Creation.

[18] Cf. E. Haeckel, Systematic Phylogeny, vol. i.

[19] Cf. Anthropogeny and Natural History of Creation.

[20] Cf. Natural History of Creation.

[21] See chaps. xvi. and xvii. of my Anthropogeny.

[22] E. Haeckel, A Visit to Ceylon.

[23] Cf. Monism, by Ernst Haeckel.