126 



on transverse sections, in typical arrangement as described by Wolffhiigel, 

 only that (in *S. hepatica and in S. centrijmnctata) it is connected with the 

 uterus and not with the ovary. Out of this organ the egg-pouches develop ; 

 the eggs leaving the uterus, which atrophies, finally collect in the egg- 

 pouches. 



Topography of a Segment at Male Sexual Kipeness. 



The genital organs, as has already been explained, open irregularly 

 alternately to the right or left. 



At the stage when the spermatozoa are maturing and the first have 

 reached the receptaculum seminis, the genital organs, which all lie in the 

 transverse plain, are composed as follows : — 



There are three, four, or more testes on each side of both right and 

 left ventral canals, lying slightly dorsally ; all contain spermatozoa and 

 also spermatoblasts. Vasa efterentia can be fo\ind upon very careful 

 search; they appear to run from the testicle direct to the vas deferens. 

 The vas deferens crosses the dorsal side of the median zone, quite close to 

 the transverse muscles, from the aporose to the pore side. Just before 

 reaching the cirrhus pouch, laterally to the ventral canal, it becomes much 

 dilated and crammed with spermatozoa and is no longer straight, but 

 wound in a few spirals. Having entered the cirrhus pouch it is wound 

 up in a number of convohitions, still filled with spermatozoa ; the terminal 

 portion is straight, easily distinguishable by the dark blue staining of the 

 ciliated layer next to its lumen. The length of this ciliated portion is 

 63 //. ; breadth about 3 f/.. The genital pore is extremely small, probably 

 no longer functional. The end of the cirrhus bends over and joins the 

 vagina ; it is not introduced into the vagina, but appears to be fused to 

 the end of it. (Fig. 6.) There is a short, very narrow connection between 

 vagina and pore. 



SCHKMATic Diagram of the Principal Organs at Male Sexual Maturity. 



