12 Art - 4 - S. Goto and H. Kiknchi : 



body (fig. 1, 2, G). The wall of the uterus presents a peculiar 

 structure, inasmuch as it consists of large pyramidal cells with 

 distinct membrane, vacuolated cytoplasm and vesicular nuclei, 

 sitting on the basement membrane with their bases and projecting 

 into the uterine lumen, reducing it to a narrow space. The 

 number of these cells is four or five in one cross section, and they 

 remind one in some respects of the tentacular endodermal cells of 

 hydroids; they probably function as valves to retain the egg in 

 the ootype while in process of formation (fig. 0, b). 



The vitellaria of the two sides may be separated or continuous 

 both in front and behind according to the degree of their de- 

 velopment, and accompany the intestinal cocca from their front to 

 their hind end, or may even extend a little further backwards, 

 enclosing them on the dorsal and ventral sides as well as laterally. 

 The lobed structure is very apparent and the lobes are compara- 

 tively large for the size of the animal. The paired ducts originate 

 shortly in front of the ovary and are relatively large, and 

 proceeding straight towards the median line there unite to form 

 on the ventral side of the oviduct an inconspicuous yolk reservoir, 

 from which a very short unpaired duct leads into the oviduct, into 

 which it opens from the right side. The paired yolk ducts form a 

 transverse bridge across the body. 



Close behind the opening of the yolk duct, the oviduct 

 receives on its ventral side another canal, the vaginal, which 

 proceeds from thence obliquely towards the right and the dorsal 

 side, passing close behind the transverse yolk duct and between 

 the intestinal cœcum and the viteilarium and opens on the dorsal 

 surface of the body at some distance from the lateral margin. 

 The vaginal canal very gradually enlarges as it proceeds dorsal- 

 wards and is expanded like a funnel' at its external opening; it is 

 lined by a structureless membrance, which is directly continued 

 onto the cuticle of the body and is quite thick in the terminal 

 portion of the canal; it is richly provided with circular muscle 

 fibres for nearly half its course from the external opening, which 

 is very conspicuous both in living specimens and total mounts as 

 well as in sections. In the neighbourhood of the vaginal canal 



