NOTES ON TWO NEW SPECIES OF JAPANESE POLYCLADS. 



593 



features, consisting, as it does, of two sorts of cells, glandular and 

 non-glandular, of which the latter sort is the more numerous. 



Male Genital Organs. — Numerous small testes, containing sperma- 

 tozoa in all stages of development, are situated in the ventral half of 

 body between gut branches. Probably they are all connected together 

 by an anastomosing system of testicular ductules, but these could not 

 be definitely made out. A pair of vas deferens run along the sides of 

 pharyngeal pocket, increasing in thickness as they proceed posteriorly. 

 Not far behind the posterior end of pharynx each vas deferens abrupt- 

 ly bends inward, finally to open, side by side with its fellow of the 

 opposite side, into a moderately large seminal vesicle with muscular 

 wall. The vas deferens shows a definite wall consisting of a thin 

 epithelium and a feeble layer of circular muscular fibres. The seminal 

 vesicle rises from below upward, obliquely posteriorly inclined ; at the 

 same time it gradually narrows and passes above into the slender 

 ejaculatory duct. This duct, after receiving that from the prostatic 

 gland on the dorsal side, makes an abrupt, obliquely posteriorly and 

 downwardly directed bend, soon to enter the base of penis and finally 

 to open at the tip of this. 



The prostatic gland, situated immediately anterior and dorsal to 

 the seminal vesicle, is of an oblong shape. It is internally lined with 

 a non-ciliated epithelium of a glandular nature and externally with a 

 layer of parenchyma including numerous muscular fibres. 



The penis is a long and slender tubular body, hanging from above 

 subvertically in the tubular penis-sheath. The sheath forms a small, 

 annular, obliquelly upwardly directed outbulging, the antrum, before 

 opening externally by the male genital pore, which is situated neir 

 the anterior border of the last quarter of body. 



Female Genital Organs. — The ovaries occur in the dorsal parts 

 of body. The oviducts are only partially demonstratable. The two 

 uteri are wide tubes containing numbers of ripe eggs ; anteriorly and in 

 front of the pharyngeal pocket they are continuous with each other 



