INTERNAL PARASITES 67 



serious menace to the flock, killing many birds. The symp- 

 toms are similar to those produced in chickens by round 

 worms. 



TAPEWORMS. (Flat Segmented Worms.) 

 Tapeworms iiiha])it the intostmal tracts of all 

 species oi" birds, animals and man. More than 

 thirty different species of tapeworms liave been 

 recorded in poultry. 



Tapeworms differ from romid worms, in that 

 they have no complete digestive tract, are flat and 

 segmented and have no distinct sex; that is, the 

 male and the female are combined in a single in- 

 dividual (hermaphrodite). The tapeworms all 

 live in the intestinal tract, in their adult stage, 

 and absorb, through their integument, nutrients, 

 taken in and digested by their host ; thus they rob 

 their liost of food nutrients. The species studied 

 in the author's laboratory are from chickens. The 

 worm is divided into a head, neck and body. The 

 head is provided with four suckers and in some 

 species a circular row of booklets. The neck in 

 some species is long, in others short, but always 

 unsegmented. The body is composed of segments. 

 These segments grow from the neck. At first they 

 are short and narrow, but become longer and 

 wider as the distance from the head increases. 

 At varying distances from the head the segments 

 become mature, that is, fully developed sexually, 

 and ready to propagate. Each segment is really 

 a separate animal and is a hermaphrodite, that is, 

 provided with both male and female generative 

 organs. Each segment impregnates itself, after 

 which the eggs are developed. As soon as the 

 segment is filled with fully developed or mature 

 eggs, the segment detaches itself, passes out with 



