112 



LEECHES 



(a) 

 (b) 



(d) 



5 mm 



Fig. 63. Details of cocoons of Erpobdella. (a) and (b) schematic 

 longitudinal sections of the cocoon of E. testacea before and after 

 the young have emerged ; (c) and (d) the same for E. octoculata 

 showing a different method of forming the terminal plugs; 

 (e) cocoon of E. octoculata with one plug removed ready for the 

 young to leave; ( f ) a cocoon emptied by a snail. From Bennike, 



1943. 





Fig. 64. Three stages in cocoon formation by Cystobranchus 

 respirans. The upper figure represents the latest stage. From 



Hoffmann, 1956. 



