42 



THE LIVER-FLUKE 



ductules of the diffuse system of yolk-glands along each side of the body. The 

 oviduct and the median vitellarian duct are surrounded at their junction by 

 the shell-gland ; and these united ducts form the wide convoluted uterus which 

 opens (beside the penis) into the common genital outlet. 



A short tube, known as Laurer's canal, runs from the junction of the oviduct 

 and the median vitellarian duct and opens by a pore on the mid-dorsal surface. 



2. Male. 



This system consists of a pair of much -branched testes lying in the middle of 

 the posterior half of the body. The branches of each testis open into a vas 



Mouth 



Anterior nerve 

 Posterior nerve- 



Piiarynx 



'Supra-cesopliageal 

 ganglion 



Subcesophageat 



ganglion 



Penia---. 

 Vesicula seminalis 



^--^arenchyma ot body 



-Ventral branches of 

 Excretory canal 



Ovary " 

 Alimentary canal 



Oviducf 

 Excretory canal 



Dorsal branches of 

 Excretory canal 



Vitelline glands- 



.Male Genital Aperturg 



-Female Genital 

 Aperture 



-Vas deferens 

 •Shell gland 



.-■Testis 



-Vitelline duct 



■"Excretory pore 



Fig. 14. — A. Dorsal View of the Liver-fluke {Fasciola hepatica), showing the alimentary oaual 

 and the excretory system ; B. Ventral View, showing the reproductive system ( x i). 



deferens, the two vasa deferentia running forward to the cirrus-sac (a depression 

 between the ventral sucker and the genital aperture or outlet) and there uniting 

 to form an elongated sac, the vesicula seminalis. From this a fine duct, the 

 ductus ejaculatorius, runs forward into a muscular organ called the penis or 

 cirrus. This opens by the small male genital pore in the common genital 

 aperture or outlet. The penis is evaginated, when the sperms are expelled, 

 and the ejaculatory duct is then telescoped inside it. 



Nervous System. 



This consists of a ring round the oesophagus with two lateral ganglia and a 

 single ventral ganglion on it. Nerves are given off from the ganglia to the 

 anterior region of the body, and from each lateral ganglion a lateral nerve runs 

 backwards under the caeca of the alimentary canal to the posterior end of the 

 body. 



