Jones, I. H. 1918. Equilibrium and Vertigo, 444 pp. 129 figs. Philadelphia. Klemensievicz, R. 1898. Neue Untersuchungen über den Bau und die Thätigkeit des Eierzellen. Mitth. d. Vereins d. Ärzte in Steiermark. 35 Jahr., pp. 45-60. Lynch, V. 1919. The function of the nucleus of the living cell. Amer. Jour. Physiol., Vol. 48, pp. 258-283. Nuttall, G. F. 1901. Blood immunity and blood relationship. London. Pfeffer, W. 1906. Physiology of plants. Trans. by A. J. Ewart, Oxford. Schaeffer, A. A. 1917. Notes on the specific and other characters of _Amoeba proteus_ (Leidy), _A. discoides_ spec. nov., and _A. dubia_ spec. nov. Arch. f. Protistenk. Vol. 37, pp. 204-228. 8 figs. Schaeffer, A. A. 1919. Investigations on the specific characters of Marine Amebas at Tortugas. Year Book No. 18, Carnegie Inst. of Wash., pp. 204-205. Todd, C. 1914. Recognition of the individual by hemolytic methods. Jour. Genetics, Vol. 3, pp. 123-130. Velten, B. 1876. Aktiv oder passiv? Oester. Bot. Zeitschr. Velten, B. 1876. Die physikalische Beschaffenheit des pflanzlichen Protoplasmas. S. B. d. Wiener Akad., Bd. 73. Walton, L. B. 1918. Organic evolution and the significance of some new evidence bearing on the problem. Amer. Nat., Vol. 52, pp. 521-547. Willows, R. S., and Hatscheck, E. 1916. Surface tension and surface energy. 2d ed. Philadelphia. FOOTNOTES: [1] Wilson (’00) describes it as _Pelomyxa_, but it has much closer affinities with _Amoeba_. It is in fact perhaps the closest relative of _Amoeba proteus_. Ectoplasm formation, and especially the formation of ectoplasmic ridges in _carolinensis_, is exactly like that in _proteus_. [2] This is shown by the fact that after this ameba has taken on a spherical shape due to some disturbance in the water, the number of small ridgeless pseudopods thrown out upon resuming movement, is about the same as in _dubia_; but after ridges begin to form, the number of pseudopods decreases. [3] That is, resemblances in nuclear division stages are not correlated with corresponding degrees of resemblance in somatic characters. It is not generally held that the shape or size or number of chromosomes is correlated with any external characters. It is the presence of hypothetical factors or genes which are held to be correlated with somatic characters and their number or arrangement in a chromosome is not in any way related to their character.