EXPERIMENTS ON THE REPRODUCTION OF THE 

 HYPOTRICHOUS INFUSORIA 



I. CONJUGATION BETWEEN CLOSELY RELATED 'INDIVIDUALS OF 



STYLONYCHIA PUSTULATA 



GEORGE ALFRED BAITSELL 



From the Sheffield Biological Laboratory, Yale University 



TWENTY FIGURES (ONE PLATe) 



. CONTENTS 



I. Introd'uction 47 



II. Methods 51 



III. Material 53 



IV. Morphology and physiology of the' non-con jugants 55 



A. Living material 55 



B. Prepared material 61 



V. Morphology and physiology of the conjugants 62 



A. Living material 62 



B. Prepared material 64 



VI. Morphology and physiology of the ex-conjugants 65 



A. Living material 65 



B. Prepared material 67 



C. Split conjugation 67 



VII. Discussion and conclusions 68 



VIII. General summary 72 



Literature cited 74 



I. INTRODUCTION 



Maupas ('88, '89), from his investigations on the phenomenon 

 of conjugation in Stylonychia pustulata, beheved that conjuga- 

 tion, in order to be fertile, must take place when the organisms 

 were at a certain stage of maturity which, in this species, occurred 

 between the 130th and 170th generations. Conjugation could occur 

 between gametes after this so-called period of sexual maturity, but 

 in such cases the union was infertile, and the ex-conjugants would 

 invariably die soon after separation. Provided conjugation did 



47 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 13, NO. 1 



