589 Eier der VûÑgel Deutschlands, 1818ã28 (cit. des Murs, p. 36).
590 Traitûˋ dãOologie, 1860.
591 Lafresnaye, F. de, Comparaison des éufs des Oiseaux avec leurs squelettes, comme seul moven de reconnaûÛtre la cause de leurs diffûˋrentes formes, Rev. Zool., 1845, pp. 180ã187, 239ã244.
592 Cf. Des Murs, p. 67: ãElle devait encore penser au moment oû¿ ce germe aurait besoin de lãespace nûˋcessaire û son accroissement, û ce moment oû¿ã...ãil devra remplir exactement lãintervalle circonscrit par sa fragile prison, etc.ã
593 Thienemann, F. A. L., Syst. Darstellung der Fortpflanzung der VûÑgel Europas. Leipzig, 1825ã38.
594 Cf. Newtonãs Dictionary of Birds, 1893, p. 191; Szielasko, Gestalt der Vogeleier, J. f. Ornith. LIII, pp. 273ã297, 1905.
595 Jacob Steiner suggested a Cartesian oval, rã₤+ã₤mãrÿ£¢ãý =ã₤c, as a general formula for all eggs (cf. Fechner, Ber. sûÊchs. Ges., 1849, p. 57); but this formula (which fails in such a case as the guillemot), is purely empirical, and has no mechanical foundation.
596 Gû¥nther, F. C., Sammlung von Nestern und Eyern verschiedener VûÑgel, Nû¥rnb. 1772. Cf. also Raymond Pearl, Morphogenetic Activity of the Oviduct, J. Exp. Zool. VI, pp. 339ã359, 1909.
597 The following account is in part reprinted from Nature, June 4, 1908.
599 Journal of Tropical Medicine, 15th June, 1911. I leave this paragraph as it was written, though it is now once more asserted that the terminal and lateral-spined eggs belong to separate and distinct species of Bilharzia (Leiper, Brit. Med. Journ., 18th March, 1916, p. 411).