18 Art. 4.— T. Kaburaki : 



nected in their course by luimerous transverse connnissures and 

 giving off numerous lateral branches towards the marginal nerve 

 plexus. 



The copulatory organs are constructed in similar manner to 

 those in BipaUum ochroleucum previously described, and embedded 

 in the muscular sheath. The common genital opening leads into 

 the wide vestibulum of an irregular contour, which receives the 

 openings of the penis-sheath and the glandular organ from above. 

 The vestibulum is lined with a single epithehum, beneath which 

 are found circular and longitudinal muscular laj^ers. Numerous 

 glands are found all round the genital aperture, into which they 

 open. 



Numerous testes are arranged in a single row just outside the 

 longitudinal nerve cords, beginning from some distance behind the 

 ovary and ceasing altogether to exist at the level of the pharynx- 

 insertion. As is well known, each testis is made up of sperm- 

 mother-cells and spermatozoa in all stages of development. The 

 vasa deferentia, which are filled with spermatozoa, pursue a back- 

 wardly directed, sinuous course along the outer side of the nerve 

 cords, and at the sides of the penis make an abrupt turn upwards 

 and forwards. After entering the penis-bulb, they fuse together to 

 form a common duct which opens into the seminal vesicle. 



The penis is composed of the bulbous basal part of strongly 

 muscular nature and the free conical intromittent part, being almost 

 horizontally disposed in the penis-sheath. The latter part en- 

 closes a relatively narrow seminal vesicle lined with a layer of high 

 columnar cells of a glandular nature. The vesicle passes behind 

 into the ejaculator}^ duct, opening into the penis-sheath at the tip 

 of the penis. The sheath communicates with the vestibulum 

 through the narrow passage. 



The paired ovary, ventral in position, is situated at a short 

 distance behind the meshwork of the brain, and at the postero- 

 lateral aspect gives rise to the oviduct in the form of a funnel-like 

 widening which soon passes into the narrow duct, proceeding 

 backwards just above the nerve cords and receiving the vitelline 

 glands at numerous points. The vitelline glands are represented 



