40 -^rt. 4.— T. Kaburaki : 



The nervous system consists, as usual, of two longitudinal 

 cords which anteriorly join the cerebral meshwork. The cords are 

 connected throughout their course by numerous fine transverse 

 commissures. Laterally they send out numerous branches towards 

 the nerve plexus. 



The common genital opening leads into the vestibulum of an 

 irregular contour, which receives the openings of the penis-sheath 

 and the glandular organ from behind. The cavity is lined with a 

 thin ciliated epithelium, external to which is a fairly well developed 

 muscular coating composed of circular and longitudinal fibres. 



Numerous testes, each consisting of sperm-mother-cells and 

 spermatozoa in several stages of development, occur close together 

 in the ventral position of the body and are arranged in a single 

 row along the outer side of the nerve cords, beginning from some- 

 what behind the ovary and extending behind to the insertion of 

 the pharynx. The vasa deferentia, filled with spermatozoa, proceed 

 straight backwards, just outside the nerve cords, and turn abruptly 

 forwards and upwards, to enter the penis-bulb at the sides, and 

 finally to unite into a common duct which communicates with the 

 seminal vesicle. 



In the penis there can be distinguished the semi-spherical 

 bulbous part of muscular nature and the free conical intromittent 

 part which is nearly horizontally disposed in the penis-sheath. 

 Enclosed in the intromittent part is a relativel}^ narrow seminal 

 vesicle, which is lined with high columnar cells of a glandular 

 nature. Posteriorly the vesicle is continuous with the ejaeulatory 

 duct, opening into the penis-sheath at the tip of the penis. The 

 muscular fibres of which the penis is composed are arranged in two 

 sets, circular and longitudinal, the fibres of the two sets occurring 

 intermingled with one another. 



The penis-sheath is in communication with the vestibulum 

 through the narrow passage lined with a cihated epithelium. 



At some distance behind the cerebral meshwork is found the 

 paired ovary which is of an oval shape and made up of ova in 

 various stages of development. From its inner lateral aspect 

 the oviduct springs in the form of a funnel-like wideniusj which 



