62 VARIOUS FORMS OF TAPEWORMS. 



by eating the viscera of those animals. Sheep have also several 

 parasitic within them, which isroduce scouring and emaciation. 

 j\luniezia expansa is often troublesome in sheep, both in Eng- 

 land and America ; it also occurs in cattle. The life cycle is 

 not known. 



" Measles " in beef is also due to a cyst called Cysticercus 

 bovis, which occurs in the skeletal muscles, heart, lymph glands, 

 and even between the convolutions of the brain and the lungs 

 and liver. The sexual stage is the tapeworm Taenia saginata, 

 the unarmed tapeworm found in man. It is almost cosmo- 

 politan, being very prevalent in Africa and Asia. It frequently 

 reaches 7 metres long. 



Tseniosis is also sometimes a very troublesome complaint in 

 fowls, but so far has received little notice in this country. 



The third order of Platyhelminthes does not concern us : they 

 are called Nemertini, most of which are free-living worms, a few 

 being parasitic in the mantle cavities of various moUusca. 



