LIMITS OF HEREDITARY CONTROL 917 
BIBLIOGRAPHY 
Daveneort, C. B. 1904 Statistical methods. New York. 
Gauton, F. 1875 The history of the twins, as a criterion of the relative powers 
of nature and'nurture. Journ. Anthrop. Inst. 
1892 Finger-prints. Macmillan, London. 
Harris, J. ArrHuR 1910 A short method of calculating the coefficient of cor- 
relation in the case of integral variates. Biometrika, vol. 7, pp. 214-218. 
Newman, H. H. anp Patrerson, J. THomas 1909 A case of normal identical 
quadruplets in the nine-banded armadillo, and its bearing on the prob- 
lems of identical twins and of sex determination. Biol. Bull., vol. 17, 
no. 3, August. 
1910 Thedevelopment of the nine-banded armadillo from the primitive 
streak stage to birth; with especial reference to the question of specific 
polyembryony. Jour. Morph., vol. 21, no. 3. 
Peart, RayMonp 1910 Intra-individual variation and heredity. Proc. Seventh 
Intern. Zool. Congress. 
Prarson, K. 1909 Determination of the coefficient of correlation. Science, 
N.S., vol. 30, pp. 23-25. 
Vernon, H. M. 1903 Variation in animals and plants. London. 
WeIsMANN, A. 1893 The germ-plasm. London. 
Witper, H.H. 1904 Duplicate twins and double monsters. Amer. Jour. Anat., 
vol. 3, no. 4. 
1908 The morphology of cosmobia; speculations concerning the sig- 
nificance of certain types of monsters. Amer. Jour. Anat., vol. 8, no. 4. 
