106 



LEECHES 



contains a granular secretion which is thought to have proteolytic 

 properties. The wall of the spermatophore is secreted by glands 

 in the wall of the atrium and the sperms are pumped into it by the 

 ejaculatory ducts. There is a base plate, perforated to allow for 

 the passage of sperm, and when the spermatophore is expelled by 

 the action of the muscles of the atrium walls the base plate adheres 

 to the body of another leech. 



Exchange of spermatophores is often accompanied by a close 

 intertwining of the bodies of the leeches (Fig. 56). The clitellar 





Fig. 56. Piscicola copulating, sp, spermatophore being 

 deposited on the copulatory area. From Grasse, 1959, after 



Brumpt. 



region is the most usual site of deposition but spermatophores are 

 not infrequently found as far away as the dorsal region of the 

 posterior half of the body. The most detailed study of the process 

 of fertilization is that of Brumpt (1900). He showed that in 



