THE MEDICINAL LEECH 



11 



glands, and a penis sheath surrounding an eversible muscular 

 penis. Spermatogonia are budded off from the walls of the testis 

 sacs and develop into spermatozoa while floating freely in the 

 contained coelomic fluid. They pass via vasa efferentia and vasa 

 deferentia into the epididymes where they are stored at the begin- 



Prostate gland — 



Ejaculatory duct 



Oviduct 



Oviduca 

 gland 



Vos deferens 



Ventral nerve cord 



Epididymis 



Penis in 

 sheath 



Ovary in 

 ovisac 



Vagina 



5 mm 



Fig. 4. Details of reproductive organs. The penis sheath, 



prostate bulb and female organs are shown with the dorsal wall 



removed. After Leuckart & Brandes, 1886-1901. 



ning of the breeding season. When required for use they pass 

 through the ejaculatory ducts to the prostate bulb where they are 

 cemented into spermatophores. The penis is used to transfer 

 them to the vagina of another leech at the time of copulation. 



