3
494 Cf. Bû¥tschli, ãProtozoa,ã in Bronnãs Thierreich, II, p. 848, III, p. 1785, etc., 1883ã87; Jennings, Amer. Nat. XXXV, p. 369, 1901; Pû¥tter, Thigmotaxie bei Protisten, Arch. f. Anat. u. Phys. (Phys. Abth. Suppl.), pp. 243ã302, 1900.
CHAPTER XI THE LOGARITHMIC SPIRAL
1
495 A great number of spiral forms, both organic and artificial, are described and beautifully illustrated in Sir T. A. Cookãs Curves of Life, 1914, and Spirals in Nature and Art, 1903.
2
496 Cf. Vines, The History of the Scorpioid Cyme, Journ. of Botany (n.s.), X, pp. 3ã9, 1881.
3
497 Leslieãs Geometry of Curved Lines, p. 417, 1821. This is practically identical with Archimedesã own definition (ed. Torelli, p. 219); cf. Cantor, Geschichte der Mathematik, I, p. 262, 1880.