INTRODUCTORY 3 



to which Codoplana also belongs. My preliminary account about the 

 animal appeared in the number of Annotat. Zool. Japon. that contained 

 the paper on Codoplana mentioned above. 



Most of the following rearch-works were carried out at the Zoo- 

 logical Laboratory of the Tokyo University during the years 191 6- 19 19. 

 I am greatly indebted to the late Professor Ijima for his kind guidance 

 and untiring encouragement all through the work. I owe also Professors 

 Watase, Goto and Yatsu much valuable advice. Further, Mr. Okubo, 

 a friend of mine, favoured me with a gift of many fine specimens of 

 Coeloplana which he had collected and fixed at Misaki. Finally, I 

 should not fail to mention the kind assistance I have received from 

 Professor Oka of the Tokyo Higher Normal School, Dr. Mortensen of 

 the Zoological Museum of Copenhagen, Dr. Ono of the Tokyo Univer- 

 sity and Dr. Terao of the Imperial Fisheries Institute of Tokyo in 

 getting literature necessary for the study. To all these gentlemen my 

 sincerest thanks are due. 



