108 BOARD OF AGRICULTURE. 



little liable to get it if pastured on uplands, or other dry 

 places, and supplied with pure spring water, by preference 

 from a trough or other similar arrangement. On the other 

 hand, sheep pastured on meadows, or swampy lands, or in 

 places where they have access to the marshy banks of streams, 

 ponds, and swamps, will be far more liable to get this and 

 several other parasites. 



An exception should, however, be made in the case of salt 

 marshes and meadows, for sheep pastured in such places sel- 

 dom get the disease. This is probably owing to the fact that 

 the fresh water snails, that harbor the young flukes, cannot 

 live in salt or brackish water. 



Smaller Liver-fluke (Distoma lanceolatum Mehlis). 



This species is also found in the bile-duct and gall-bladder 

 of sheep and cattle, and occasionally in man. It is sometimes 

 associated with the common fluke. It is much smaller, the 

 length being about one-third of an inch and the breadth an 

 eighth. It has a smooth, flat, lance-shaped body, broadest 

 behind the middle, narrowing to each end, the mouth-end 

 being most pointed. There are two suckers, as in the com- 

 mon fluke, the one at the front end having the mouth at the 

 bottom. 



The anatomy is quite different, for in this, as in all other 

 true Distomas, the digestive tube only forks once, each branch 

 remaining a simple, closed tube, running down on each side 

 of the middle region of the body. The testicles are two 

 large, roundish, but somewhat lobed organs, just below and 

 near the ventral sucker. The uterine tube has numerous 

 branches arranged on each side of a main central trunk, in the 

 hinder part of the body. The ovaries are comparatively 

 small and situated on each side of the middle region of the 

 body. 



Development. 



The eggs hatch in water, after several weeks, producing 

 very small, nearly round embryos, which have the vibrating 

 cilia only on the head end, which is a little smaller than the 

 other end. They are not such lively swimmers as the em- 



