174 



I I 



VNSEGMENTED WO RMS. 



suggests, there are two suckers an anterior, perforated by 

 the mouth ; a second, imperforate, a little farther back on 



the mid-ventral line. 



muscular 

 blind 



c.s 



v.s 



S 



There is a 

 pharynx and a 

 alimentary canal which 

 sends branches through- 

 out the body. The 

 nervous system consists 

 of a ganglionated collar 

 round the pharynx, from 

 which nerves go forward 

 and backward ; of those 

 which run backward, 

 the two lateral are most 

 important. Although the 

 larva has eye spots to 

 start with, there are no 

 sense organs in the adult. 

 The body cavity is not 

 represented unless it be 

 by minute intercellular 

 spaces in the body- 

 parenchyma. Into these 

 there open the internal 

 ciliated ends of much- 

 branched excretory tubes, 

 which unite posteriorly in 

 a terminal vesicle opening 

 to the exterior. 



FIG. 8 4 .-Structure of liver fluke. -After The reproductive system is 



Sommer. From ventral surface. The , ,., j i 



branched gut (g.) and the lateral hermaphrodite and complex, 



nerve (/.;/. I are shown to the left, the From much-branched testes 



branches of the excretory vessel (e.v.) spermatozoa pass by a pair of 



to the right. ducts (vasa deferentia) into a 



,, , , * seminal vesicle lying; in front 



., Mouth; ///, pharynx; g., lateral head i -ru 



ganglion ; v.s., ventral sucker ; c.s., position of the ventral sucker. Thence 

 of cirrus sac ; an arrow indicates the ex- they are expelled by an ejacu- 

 cretory aperture. latory duct, which passes 



through a muscular pro- 



trusible penis. The retracted penis and the seminal vesicle lie in 

 a space or "cirrus sac" between the ventral sucker and the external 

 male genital aperture. The ovary is also branched, but less so than 



711. 



