Japanese Freshwater Triclads. '[^ 



that of surrounding tissue. In sections the cellular cords of the 

 vitelline gland are seen to be attached to the surface of the giant 

 cell, but exactly how the yolk cells reach the oviduct lumen cannot 

 be elucidated. As pointed out by previous authors, the giant cell 

 in question is probably of a glandular nature. It may be that its 

 secretion disperses into the parenchyma and acts .as an attractive 

 agent, which may cause the yolk cells to collect at its position. 

 Eventually the cell breaks up and disappears, and then the yolk 

 cells may be said to be in a position to make their way unhindered 

 into the oviduct. 



The seminal receptacle is a moderately large sack-like organ 

 situated in front of the penis. Its wall is an epithelium made up of 

 large columnar cells of a glandular nature, beneath which are fine 

 muscular layers of circular and longitudinal fibres. 



The receptacle gives rise behind to the vaginal canal, which 

 runs dorsal to the penis, finally opening into the penis-sheath from 

 above and behind. The lining epithelium is made up of cylin- 

 drical cells, beneath which is a thick muscular coating composed of 

 an internal circular and an external longitudinal layer. Besides, 

 the vagina is surrounded by a large number of pyriform cells, 

 which appear to represent the unicellular glands. 



JPlanaria papiliifet^a Ij. et Kab. 

 (PI. I., figs. 7,8.— Text figs. 6.7.) 



This species was first procured by Professor Shishido in 

 November, 1889, in an old unused well in Tokyo (Ichigaya Ward). 

 Subsequently, . on several occasions, specimens were obtained by 

 him and given to the late Professor Ijijia. In May, 1890, a 

 number of cocoons apparently belonging to the species were 

 collected in the same well. According to the late Professor Ijima's 

 note, they contained embryos of about 2 mm. in length. 



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

 living state is subtruncate and weakly crenate. The gentle median 

 convexity spreads on each side into rounded lateral lobes which 

 are not produced into tentacles. The head gradually merges into 



