The seminal duct passes at its terminal part into the seminal 

 ejaculatory canal (ductus ejaculatorius) forming, for the most part, either 

 one or several widenings of varying shape and location in front of the latter, 

 which appear as reservoirs for the full, ripe sperm (vesicula seminalis 

 externa). 



HtNM 



Fig. 90. Diclybothrium armatum Leuckart, cross section of the body in 

 the region of the testes. 



As a rule this ductus ejaculatorus is supplied with a sufficiently 

 powerful musculature, it is of insignificant length and opens into the sex 

 atrium on its terminal part, or its terminal part enters into the differently 

 arranged copulatory organ, or finally it changes into a chitinous pipe which 

 represents its direct continuation. In most 

 cases a number oi monocellular or poly- 

 cellular glands of different origin opens in- 

 to the ductus ejaculatorius. These glands 

 are of two types, prostate and granule -con- 

 taining. More often they are more power- 

 fully developed among the forms with chiti- 

 nous sex armature and weaker among those 

 that have muscular copulatory organs. Pro- 

 state and granule-forming glands very often 

 especially among Dactylogyridae and types 

 close to them, form ampule-shaped reser- 

 voirs lying in direct proximity to the sex 

 pore (Fig. 92). The physiological signifi- 

 cance of these formations has not been 

 elucidated so far. 



p. 62 



0.1mm 



Fig. 91. Polystoma integer- 



rimum Froelich, frontal 



section through the seminal 

 duct ( vas d eferens ). 



The copulatory organ of mono- 

 genetic trematodes has a very diversified 

 jtructure. Basically, one can consider two 

 types of structures characteristic for them: 



in the shape of the muscular penis protruding through the sex pore, or in the 

 shape of a completely chitinous formation. The main peculiarity in M .no- 

 genoidea is the absence among them of the turning inside out, (eversil le, 

 nobis ) muscular sac enclosed in a special cirrus which is so characte ^-istic 

 and Trematoda. 



for Cestoldea 



All indications of the presence of cir: > among 



57 



