JOURNAL OF THE COLLEGE OF SCIENCE, TOKYO IMPERIAL UNIVERSITY. 



VOL. XLIV., ART. 2. 



On some Japanese Freshwater Triclads ; with a 



Note on the Parallelism in their Distribution in 



Europe and Japan. 



By 



Tokio Kaburaki. 



Zoological Institute, Science College, Imperial University, Tokyo. 



tT7?/i 1 plate and 14 text figures. 



A considerable number of the freshwater Triclads have, up 

 to date, been recorded by several investigators as occurring in 

 various parts of the globe. With regard to the systematic classifica- 

 tion of them, if sliould be remarked that the group is now in a 

 very confused condition, so that they require a thorough revision 

 at once. It may be noticed here that tlie genus Planaria hitherto 

 referred to shows a difference in form of sufficient value to separate 

 the two or more groups gt-nerically. In the present paper, however, 

 I have intentionally abstained from making any such attempt, 

 leaving the problem to those who may have occasion to study 

 personally a large number of forms and especially to re-examine 

 the species previously described. I have now confined myself to 

 the^ further report of ten species previous^ placed on record as 

 occurring in the territories of Japan. But the species described b}^ 

 Stimpson (75) under the name of Planaria badia from Loo Choo 

 and PI. cinerea from Ohsliima — both seeming perhaps to stand in 

 conjunction with PI. gonocephala — are left out of consideration in 

 this paper, since they are decidedly meagre in description. 



