TREMA TOD A. 



165 



In the sheep it causes the serious disease called liver rot. 

 The animal is flat, oval, and leaf-like, measures about an 



Fig. 52. — Structure of Liver Fluke. (After .Sommer.) 

 From ventral surface. The branched gut (gn.) and the 

 lateral nerve (l.n.) are shown to the left, the branches of 

 the e.xcretory vessel (e.v. ) to the right. 



;«, Mouth ; ph, pharyn.v ; g^ lateral head ganglion ; v.s, ventral 

 sucker ; cj, position of cirrus sac ; an arrow indicates the excretory 

 aperture. 



inch in length by half an inch across the broadest part, 

 varies from reddish brown to grayish yellow in colour. As 

 the word Distoma suggests, there are two suckers, — an 



