l'RELIM I NARY DESCRIPTIONS OF SOME JAPANESE TRICLADS. 



155 



3. Procerodes trigonoccpliala, n. sp. Outline 

 of body in the creeping state, about 

 16X. 



4. Same. Diagram of sexual organs. 



at atrium, vd' common vas deferens, 

 vs vesicula seminalis. 

 Other letters as in woodcut 2. 



Large specimens in the creeping state 4 mm. long and I mm. broad ; 

 commonly smaller. 

 3 4 Body translucent, gen- 



erally somewhat whitish ; 

 frontal margin and the 

 region of eyes darkish ; 

 central region of head whit- 

 ish ; alimentary tracts ap- 

 pearing brownish, reddish 

 or orange in color. 



Eyes two, small, each 

 surrounded by a clear space, 

 situated far behind anterior 

 body-end, the distance being 

 more than three times that 

 between the eyes. The 

 latter distance is about equal to one-half that between either eye and lateral 

 body margin of the same side. 



Mouth at about the hind end of the middle third of body. Pharynx 

 inserted a short distance behind the middle of body. Anterior gut trunk 

 with 7-9 pairs of branches ; each posterior gut trunk with about 10 

 branches on both sides, those of inner sides being very short. 



Genital aperture situated half-way between mouth and posterior body- 

 end. Atrium simple. Testes numerous, small, situated ventrally in body 

 and arranged on both sides of lateral nerve-cords from close behind ovaries 

 to insertion of pharynx, but farther behind only on the outer side of same, 

 ceasing altogether to exist at about the level of mouth. Vasa deferentia 

 uniting in penis bulb into a short common duct, which soon opens into 

 moderately wide and smooth-walled vesicula seminalis; the latter narrowed 

 inferiorly into ductus ejaculatorius terminating at tip of penis, which is of a 

 conical shape and subvertically disposed. Ovaries two, lying ventrally 

 between fourth and fifth pairs of gut branches. Oviducts of both sides 



