511 



Pearl, R. and F. M. Surface, A Biometrical Study of Egg Production 

 in the Domestic Fowl. I. Variation m Annual Egg Production. 

 M. S. Department of Agriculture, Bureau of Animal Industry. 1909. 



Pearl, R. and F. M. Surface, Is there a cumulative effect of Selection? 

 Zeitschr. f. indukt. Abst.- u. Vererbungsl. 2. 1909- 



, Studies on Hybrid Poultry. Maine Agricult. Exp. Station. Pap 



fr. the Biol. Labor. 21. mio. 



, On the inheritance of the barred color pattern in poultry. Aren. 



f. Entwm. 30. 1910. 

 Pearl, R., assisted by O. M. Pepper and F. J. Hagle, Variation and 



differentiation in Ceratophyllum. Carnegie Institution Publications, 



Washington. 58. 1907. 

 Pearson, K., The Chances of Death and other Studies in Evolution. 



London 1897. 

 --, Mathematical Contributions to the Theory of Evolution. On the Law 



of Ancestral Heredity. Proc. Roy. Soc. London. H2. 1898. 

 * , The Grammar of Science. 1900. 

 , The Law of Ancestral Heredity. Appendix II: On Inheritance (Grand- 



parent and Offspring) in Thoroughbred Racehorses, by Norman 



Blanchard. Appendix III: by Alice Lee. Biometrica. 2. 



190203. 

 , On the Ancestral Gametic Correlations of a Mendelian Population 



mating at random. Proc. Roy. Soc. London. 81. 1909- 

 , Darwinism, biometry and some recent biology. I. Biometrica. 7. 



1910. 

 , A. Lee and A. Wright, A cooperative study of Queens, drones, and 



workers in Vespa vulgaris. Biometrica. 5. 1907. 

 Perez, J., Memoires sur la ponte de l'abeille reine et la theorie de Dzierzon. 



Ann. Sc. Nat. Zool. 7. 1878. 

 , Des effets du parasitisme des Stylops sur les Apiaires du Genre Andrena. 



Act. Linn. Soc. Bordeaux. 3. 1880. 

 Pergande, Th., The Life-History of Two Species of Plant Lice inhabiting 



both the Witch Hazel and the Birch. U. S. Dept. Agricult. 1901. 

 , North American Phylloxerinae affecting Hickories (Carya) and Other 



Trees. Proc. Davenport Soc. Davenport, Jova.- 9. 1904. 

 Peter, K., Experimentelle Untersuchungen ber individuelle Variation 



in der tierischen Entwicklung. Arch. f. Entwm. 27. I99- 

 Petr unkewitsch, A., Die Richtungskrper und ihr Schicksal im befruch- 

 teten und unbefruchteten Bienenei. Zool. Jahrb. 14. 1901. 

 , Gedanken ber Vererbung. Speyer und Kaerner 1904. 

 Pfeffer, W., Untersuchungen ber die Entstehung der Schlaf bewegungen 



der Blattorgane. Abh. d. Math.-Phys. Kl. d. K. Sachs. Ges. d. Wiss. 



1907. 

 , Die Entstehung der Schlafbewegungen bei Pflanzen. Biol. Zentralbl. 



1908. 



