G2 WORM PARASITES. 



These are the Cestodes or Tapeworms (fig. 19), and 

 the Trematodes or Flukes. The former being ribbon- 

 like, the latter leaf-like in form. 



Tapeworms are nearly always segmented ; the 

 adult form lives in the intestines, the earlier stages 

 in various organs of the body — two distinct hosts for 

 these stages being necessary. 



The Flukes are always unsegmented. 



Of the Nemathelminths only one group is parasitic 

 upon Poultry, namely, the Nematodes or Thread- 

 worms, which are elongated and thread-like in form 

 and attenuated at each extremity. 



The diseases and pathological peculiarities invoked 

 by the presence of certain of these groups will be 

 discussed in the following article. A complete list 

 of all that have been recorded within Gallus domes- 

 ticus will be found in the Appendix. 



A. Cestoda or Tapeworms. 



Cestode worms are often most troublesome in 

 animals, and occasionally they become pathologically 

 important in domestic birds. Twelve species have 

 been recorded as guests of the Fowl. By virtue of 

 their numbers they often produce what is known as 

 Tceniosis, wdiich may end fatally. 



Most of the Cestode worms have a very compli- 

 cated life-history. They nearly all require two hosts 

 in which to develop during their cycle of life. The 

 Tapeworms are a group of the flat worms, or, as they 



