224 Regulation of Size in Unicellular Organisms 



tions of frequency are really samples of the same population, with 



special reference to recent work on the identity of Trypanosome 



strains. Biometrika, 10, 85-143. 

 Peebles, F. 1912 Regeneration and regulation in Paramecium cau- 



datum. Biol. Bull., 23, 154-170. 

 Penard, E. 1889 Etude sur quelques Heliozoaires d'eau douce, 



I. Arch, de Biol., 9, 123-183. 

 Penard, E. 1890 Etudes sur les Rhizopodes d'eau douce. Mem. soc. 



phys. hist. nat. Geneve, 31, 1-230. 

 Penard, E. 1902 Faune rhizopodique du bassin du Leman. Geneve, 



714 pp. 

 Penfold, W. J. 1914 On the nature of bacterial lag. Jour. Hyg., 



14, 215-241. 

 Penfold, W. J., and Norris, D. 1912 The relation of concentration 



of food supply to the generation time of bacteria. Jour. Hyg., 12, 



527-531. 

 Peskett, G. L. 1924 Allelocatalysis and the growth of yeast. Bio- 



chem. Jour. 18, 866-871. 

 Peskett, G. L. 1925 Studies on the growth of yeast. I. The influence 



of volume of culture medium employed. Biochem. Jour., 19, 464- 



473. 

 Peskett, G. L. 1927 Studies on the growth of yeast. III. A further 



study on the influence of volume of medium employed. Biochem. 



Jour., 21, 104-110. 

 Peters, A. W. 1904 Metabolism and division in protozoa. Proc. 



Amer. Acad. Arts Sci., 39, 441-516. 

 Peters, R. A. 1929 Observations upon the oxygen consumption of 



"Colpidium colpoda". Jour. Physiol., 68, ii-iii. 

 Petersen, W. A. 1927 The axial gradient in Paramecium. Sci., 66, 



157-158. 

 Petersen, W. A. 1929 The relation of density of population to rate 



of reproduction in Paramecium caudatum. Physiol. Zool., 2, 221- 



254. 

 Pfitzner, W. 1886 Zur Kenntnis der Kerntheilung bei den Proto- 



zoen. Morphol. Jahrb., 11, 454-467. 

 Phelps, L. A. 1926 Experimental analysis of factors concerned in 



division in Ameba. Trans. Amer. Micr. Soc, 45, 133-145. 

 Poljansky, G. 1926 Die Conjugation von Dogiella sphaerii (In- 

 fusoria, Holotricha, Astomata). Arch. Prot, 53, 407-434. 

 Popoff, M. 1907 Depression der Protozoenzelle und der Geschlechts- 



zellen der Metazoen. Arch. Prot., Suppl. 1, 43-82 

 Popoff, M. 1908 Experimented Zellstudien. Arch. Zellf., 1, 245- 



379. 

 Popoff, M. 1909 Experimented Zellstudien. II. Ueber die Zell- 



grosse, ihre Fixierung und Vererbung. Arch. Zellf., 3, 124-180. 



