Terrestrial PJanarians from Japanese Territories. 



11 



I 



/IS 



9(^ 



two lateral zones, which extend from somewhat behind the ovary 

 to the insertion of the pharynx. The vasa deferentia, proceeding 

 .straiglit backwards, make an abrupt forward bend at the sides of 

 the penis, to enter the base of the penis and then finally to unite 

 into a common duct just before opening into the lumen of the 

 penis. 



In the penis there 

 can be distinguished 

 the bulbous part of 

 muscular nature and 

 ■ the conical intromit- 

 tent part, lying almost 

 horizontally in the 

 penis-sheath. Enclo- 

 sed in the latter part 

 is the wide seminal 

 vesicle with ;in anteri- 

 or wall which pi'ojects 

 into the lumen in 

 folds. Tlie cavity di- 

 rectly opens into the 

 penis-sheath at the tij) 

 of the intromittent 

 part, without passing 

 through the ejacula- 

 tory duct. Fosterioi-ly 

 ^the penis-sheath is 



Text fif;. 3. Copulatory organs of B. vnomnn in sagittal 

 secti(.n, diagramuiatically showr. 

 (iv genital vtstibnlum. 

 other letters as in text fig. 1. 



continuous with the narrow passage which opens into the posterior 

 outbulging of tlie vestibulum, near the tip of the conical process. 

 Its actual wall is formed- by a single layer of columnar cells, beneath 

 which comes a nuiscular coating. 



At a short distance behind the meshwork of the brain is seen 

 the paired ovary which is nearly oval in shape and consists of ova 

 in several stages of development. The oviduct leaves the ovary in 

 the form of a funnel-like widening, which soon assumes the charac- 

 ter of a narrow duct, running outside the nerve cords and receiving 



