JOURNAL OF THE COLLEGE OF SCIENCE, IMPERIAL UNIVERSITY, 

 TOKYO, JAPAN. 



VOL. XXVII., ARTICLE 17. 



Experiments on Germinal Localization in the 

 Egg of Cerebratulus, 



By 

 Naohide Yatsu. 



Introduction. 



To supplement tlie works of Wilson, Zeleny and myself, I 

 undertook six years ago, an experimental study of the problems 

 of germinal localization in the egg of Cerebratulus ladeus. At 

 the outset, a general outline of the work, inckidiug all conceiv- 

 able forms of experiments suited to the solution of the present 

 problem was carefully mapped out. When it came to the actual 

 execution of the experiments, however, there arose in some of 

 them technical difficulties which were too great to be overcome, 

 and only in twenty-three series was I able to arrive at fairly 

 definite and satisfactory results. Experiments were carried out 

 in the summer of 1904 and 1905 at South Harpswell, Maine as 

 a continuation of the work done in the previous year, and 

 their general results were worked out in the autumn of 1905 at 

 Columbia University. Further experiments were performed in 

 the spring of 1906 at Naples^ and again in the summer of 1907 

 at South Harpswell. 



1 The part of the work wh'ch extended from the summer of 1G05 to the spring of 

 1906 was carried out on a grant from the Carnegie Institution of Washington, for which 

 I here express my sincere thanks. 



