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as "brood capsules," from which numerous "heads," or secondary 

 scolices, are budded out, so that hundreds of these parasites may be 

 produced from a single egg. From its size alone we may judge how 

 dangerous to life such a parasite must be. Therefore, Beware of the dog.' 

 Especially never allow it to lick your face or hands. 



ORDER II.: TREMATODE WORMS, OR FLUKES 

 (TREMATODA). 



The trematode worms are flat-worms, which live parasitically on or in 

 other animals. Unlike tape-worms, they possess an unsegmented, 

 generally leaf-like body. They are provided with one or several suckers, 

 by which they adhere to the body of their host. The intestine is 

 bifurcated, and there is no anus, its function being performed by the 

 mouth. 



Of the numerous species contained in this order, we shall only 

 mention one, the Liver Fluke (Fasciola hepatica). This parasite is 

 only about an inch long, and inhabits mostly the bile-ducts of the liver 

 (name), especially of sheep, in which animal it causes the disease known 

 as " rot," by which whole flocks are often exterminated. The parasite 

 passes through a very complicated development (the larva bores its way 

 into a small water-snail, and multiplies by repeated division in the 

 interior of the host), and is probably swallowed, while encysted upon 

 wet grass, by sheep on their pastures. 



