296 DAVID DAY WHITNEY 



9. A scanty or poor diet of pure cultures of the green flagellate, 

 Chlamydomonas pulvisculus, causes nearly all female-producing 

 females to be produced whereas a copious or superabundant diet 

 of the same pure cultures of the flagellates causes nearly all male- 

 producing females to be produced. 



10. A poor or scanty diet causes only female-producing fe- 

 males to be produced but a plentiful diet of the right kind causes 

 nearly all male-producing females to be produced. 



December 6, 1915 



LITERATURE CITED 



Lauterborn 1898 Ueber die zyklische Fortpflanzung limnetischer Rotatorien. 



Biol. Centralb., xviii. 

 MoRO, LiNA 1915 Partenogenesi e anfigonia nei Rotiferi. Ricerche speri- 



mentali sul Branchionus pala. Bios, vol. 2, Fasc. 3, pp. 219-264. 

 Punnet, R. C. 1906 Sex-determination in Hydatina, with some remarks on 



parthenogenesis. Proc. Roy. Soc, B, vol. 78, pp. 223-231. 

 Shull, a. F. 1910 (a) The artificial production of the parthenogenetic and 



sexual phrases of the life cycle of Hydatina senta. Amer. Nat., vol. 



44, pp. 146-150. 



1910 (b) Studies in the life cycle of Hydatina senta. I. Artificial 

 control of the transition from the parthenogenetic to the sexual method 

 of reproduction. Jour. Exp. Zool., vol. 8, pp. 311-354. 



1911 Studies in the life cycle of Hydatina senta. II. The role of 

 temperature, of the chemical composition of the medium, and of 

 internal factors upon the ratio of parthenogenetic to sexual forms. 

 Jour. Exp. Zool., vol. 10, pp. 117-166. 



Whitney, D. D. 1907 Determination of sex in Hydatina senta. Jour. Exp. 

 Zool., vol. 5. 



1908 The desiccation of rotifers. Amer. Nat., vol. 42, pp. 665-671. 

 1910 The influence of external conditions upon the life cycle of Hy- 

 datina senta. Science, N. S., vol. 32, no. 819, Sept. 9. 

 1914 The production of males and females controlled by food condi- 

 tions in Hydatina senta. Science, N. S., vol. 39, no. 1014, pp. 832- 

 833, June 5. 



1914 The influence of food in controlling sex in Hydatina senta. 

 Jour. Exp. Zool., vol. 17, pp. 545-558. 



