GO WORM PARASITES. 



IV. WORM PARASITES. 



No less than thirty-six distinct species of Worms 

 live as parasites in the various varieties of Fowls. 

 The Worms form one of the greatest parasitic groups 

 of animals. Some of these parasites are distinctly 

 injurious to their ' host,' whilst many others seem to 

 cause no inconvenience unless they are superabundant, 

 then symptoms of their presence may make them- 

 selves obvious. Some of the vermiceous pests of the 

 Fowl appear epizootically, but the majority only 

 occur in isolated individuals. Worms are answerable 

 for at least one well-known disease in our domestic 

 birds, especially the fowl and the pheasant. The 

 latter more especially when artificially reared con- 

 tinuously on the same ground. This malady is 

 ' Gapes,' and is perhaps as serious a parasitic disease 

 as any from which poultry suffer. 



The Worms (Vermes) are one of the lower inver- 

 tebrate groups of animals that are characterized by 

 their bilateral symmetry _, the absence of articulated 

 limbs, the presence of curious paired excretory vessels, 

 and the general segmented form of the body. 



There is such a vast number of diverse forms 

 that it is almost impossible to give all their varied 

 characters. They may develop direct from the egg, or 

 they may go through a complicated metamorphosis. 

 Worms are found in every conceivable locality. 



