2 Art. 2.— T. Kahiiraki : 



In this communication, in addition to giving an account of 

 the habits, I will make a suggestion with regard to the parallelism 

 in the distribution of the freshwater Triclads in Europe and Japan, 

 with abrief consideration of the causes underlying this distribution 

 in the two regions. 



It might particularly be mentioned here that some of the 

 coloured illustrations which are embodied in the present paper 

 were made by the late Professor Lsao Ljima from the living worms. 

 To him my hearty thanks are due for much valuable aid rendered 

 me during the work. 



The species dealt with in the present paper are shown in the 

 following key: 



A. Eyes 2 (rarely 3 or 4). 



al Frontal margin thrown into some adhesive folds on the 

 inferiorly turned swollen edge. 

 a'-. Body large; median head lobe strongly arched; laternl 



lobes not prominent; colour reddish brown 



1 • Bdellocephala annandalel Lt. et ka j?. 



b-. Body moderately large; median head lobe as in the 

 preceding; colour olive-like brown, sometimes velvety 



black 2. Bdellocephala brunnea I.r. et K a tî. 



b'^. Frontal margin exhibiting no adhesive folds. 

 c^ . With tentacles. 



a^. Tentacles moderately long, obtusely pointed at tip; 



body blackish or dark oHve-like brown in colour 



, 3. Planaria vivida Ij. et Kai;. 



Ä'l Tentacles short, rounded at tip; body colourless, trans- 

 lucent 4. Planar in pellvcida It. et Ka n. 



d^. Without tentacles. 



c'l Head triangular, with lateral processes and auricular 

 sense organs slenderly reniform ; colour varial)le, usually 



olive-like brown 5. Planaria gonocephala Duges. 



d^~ Frontal margin subtruncate; body of a grayish colour, 

 witli a linear series of small papillae in tlie mid-dorsal 

 hne 6. Planaria papilllfcni l.J. et Kaw. 



B. Eyes numerous. 



