324 PROTOZOA 



(Protozoa, Ciliata) with special reference to nuclear phenomena. 



Biol Bull, 73, 397. 

 Wichterman, R. 1948. The time schedule of mating and nuclear events 



in the conjugation of Paramecium bursaria. Titrtox News, 26. 

 Wichterman, R. 1950. The occurrence of a new variety containing 



two opposite mating types of Paramecium calkinsi as found in sea 



water of high salinity content. Biol Bull, 99, 366. 

 Wichterman, R. 1951. The ecology, cultivation, structural character- 

 istics and mating types of Paramecium calkinsi. Proc. Penn. Acad. 



Sci,, 25, 51. 

 Wichterman, R. 1953. The Biology of Paramecium. McGraw-Hill- 



Blakiston Co., New York, N.Y. 

 Wood, H. K. 1953. Some Factors Affecting Delayed Separation of 



Conjugants in Paramecium aurelia. Thesis, Indiana University, 



Bloomington, Indiana. 

 Woodruff, L. L., and H. Spencer. 1924. Studies on Spathidium spa- 



thula. II. The significance of conjugation. /. Exptl Zool, 39, 133. 

 Wright, S. 1940. Breeding structure of populations in relation to speci- 



ation. Am. Naturalist, 74, 232. 



