Japanese Freshwater Triclads. 39 



tibulum. Internally the canal is lined with an epithelium of non- 

 ciliated columnar cells, beneath which is a muscular coating, being 

 continuous with that of the receptacle. Perforating the wall and 

 opening into the lumen are the ducts of a great number of unicel- 

 lular glands. 



Poif/eetis finriculfita I J. et Kab. 



(PI. I., figs. 13, 14.— Text figs; 12, 13.) 



This is a fairl}^ common species in the hilly districts of Jajjan. 

 Numerous specimens have been captured in both cool running and 

 standing waters at the following localities: Nikko; Mt. Iwate in 

 Prov. Rikuchu; in the neighbourhood of Lake Towada in Prov. 

 Mutsu; Ozawa in Prov Ugo; Mt. Bantai in Prov. Iwashiro. 



Form and Dimension.. — The frontal margin of the body in the 

 living condition is sul)ti"uncate and shows a gentle median con- 

 vexity which passes latej'all^y into the frontal margin of the 

 moderately distinct tentacles, rounded at the tip and shortl}^ 

 anteiiorly directed. The head merges into the trunk, without 

 being marked ofï by an}^ neck-like narrowing. The trunk, being 

 superiorly convex and inferiorly tiat, is slender and presents lateral 

 margins running iieai'ly parallel for the most part. The hind end 

 of the body is rounded rather than obtusely pointed. Exceptional- 

 ly large forms in the fully extended state reach 25 mm. in length 

 and about 3-5 mm. in breadth, but the species is commonly small- 

 er and measures 10-15 nim. long by 1-1-5 mm. broad in the 

 creeping state, the breadtli and length being in the ratio of 1 : 

 7- 10. 



Coloimdion. — Dorsally the body is generally of a sepia-brown 

 colour, tlie guts indistinctly showing themselves in a dark brownish 

 colour or in a variety of otber colours incidental to gut contents. 

 The ventral surface is of a paler colour than the dorsal. 



Eyes. — The extremely small eye-spots occur in great abun- 

 dance and number 30-73 (jn either side, increasing in number with 

 the growth of the l;)ody. They are distributed in a hoi'se-shoe- 

 shaped tract close to the head-margin, there commonly existing 



