PRELIMINARY DESCRIFPIONS OF SOME JAPANESE TRICLADS. 



grayish, due to scanty development of pigments ; lighter in the median 

 zone, in which the dorsal papillae again frequently appear as blackish spots. 

 Young and small individuals quite or nearly colorless. 



Eyes two, each surrounded by a colorless area, situated in the region 

 of neck ; distance between them less than that between either of them and 

 lateral neck margin, and very much less than that between them and frontal 

 margin. 



Mouth opening between middle and posterior thirds of body. Pharynx 

 inserted at about the middle of body length. Anterior main gut provided 

 with 8— g pairs of branches ; posterior trunk with 14-17 external branches 

 and with about as many, very small, internal branches. 



Genital aperture at about the middle of the posterior third of body. 

 Testes numerous, found on both sides of anterior gut trunk and also outside 

 of posterior gut branches ; mostly in ventral, but some in dorsal, parts of 

 body. Vasa deferentia entering penis separately on the sides. Vesicula 

 seminalis very wide, smooth-walled ; ductus ejaculatorius narrow, and open- 

 ing at tip of penis. Intromittent part of penis conical, horizontally lying. 

 Ovaries two, situated in front of the first pair of gut branches in ventral 

 position. A pair of large and lobed paraovaries present in front of ovaries. 

 Oviducts unite into a single short duct before opening into elongate atrial 

 passage on the dorsal side. Receptaculum seminis large, irregular-shaped, 

 dorsally situated in front of penis, sending out vagina posteriorly over penis. 



Locality: — The species was first discovered in November, 1889, by 

 Professor Shishido in an old unused well in Tokyo (Ichigaya Ward). Sub- 

 sequently, on several occasions, specimens were obtained by him and given 

 to Ijima. In May, 1S90, a number of cocoons apparently belonging to the 

 species were collected in the same well. They contained embryos of about 

 2 mm. length. 



8. Planaria vivifia, n. sp. 



Woodcuts 16 and 17. 

 Frontal margin subtruncate, gently arched in the middle, laterally 



