1. Alverdes, F. 1927.Social life in the animal world, 216New York: Harcourt, Brace.
2. Avery, G. T.The congenital behavior of the guinea pig40 Ph.D. Thesis, Stanford Univ., 1924. (Summarized by Stone, C. P. Recent contributions to the experimental literature on native or congenital behavior. Psychol. Bull., 1927, 94.)
3. Brehm, A. E. 1922. Leipzig: Thierleben.
4. Correlated anatomical and physiological studies of the growth of the nervous system in amphibia. VI. The mechanism of integration in amblystoma punctatum