[88] The reader is referred for details to the writer’s book on the subject.

[89] Robertson, T. B., Arch. f. Entwcklngsmech., 1912, xxxv., 64.

[90] Loeb, J., Über den chemischen Charakter des Befruchtungsvorgangs, etc., Leipzig, 1908.

[91] v. Knaffl, E., Arch. f. d. ges. Physiol., 1908, cxxiii., 279.

[92] Loeb, J., Artificial Parthenogenesis and Fertiliza­tion, p. 255.

[93] It has been stated by several writers that the eggs of the sea urchin can no longer form the fertiliza­tion membrane when the jelly surrounding the egg is dissolved. The writer has found that if the jelly surrounding the eggs of Strongylo­centrotus purpuratus is dissolved by acid the eggs still form a fertiliza­tion membrane upon the entrance of a spermato­zoön.

[94] Loeb, J., Artificial Parthenogenesis and Fertiliza­tion, 1913, p. 250 and ff.

[95] Delage, Y., Arch. d. Zoöl. expér. et gén., 1902, x., 213; 1904, ii., 27; 1905, iii., 104.

[96] Lillie, R. S., Jour. Biol. Chem., 1916, xxiv., 233.

[97] It is necessary to call atten­tion to the fact that sugar solu­tions of a high concentra­tion (e. g., m solu­tions) have a much higher osmotic pressure than that which they should have theoretically (Lord Berkeley and Hartley). Delage by ignoring this fact has misinterpreted his experi­ments with sugar solu­tions. See Lloyd, D. J., Arch. f. Entwcklngsmech., 1914, xxxviii., 402.