260 



PARASITIC DISEASES 



small intestine. The Echinorhyuclius is not as common a parasite 

 as the Asearide, and it is not usually present in large numbers. 

 Usually, not more than a half-dozen of these worms are found 

 in the intestine of a hog, but in some localities and in hogs that 

 are allowed to root around manure piles and in clover pastures 

 the herd may become badly infected with them and serious 

 losses occur. The average length of the male is about 3 inches 

 (8 cm.) and the female 10 inches (26 cm.). 



The Trichocephalus crenatus or whip u'orm (Fig. 77) is 

 slender or hair-like in its anterior two-thirds and thick pos- 



FiG. 77. — Whip-worms attached to wall of intestine. Fig. 78. — Pin worms in iniesuuc. 



teriorly. It is from 1.5 to 2 inches (40 to 45 mm.) long. It 

 is found in the ca?cum attached to the wall by the hair-like 

 portion. 



The (J^sophagostomum dcntaium or pin ivorm is from 0.3 to 

 0.6 inch (8 to 15 mm.) long. It is found in the large intestine 

 (Fig. 78). 



The sijmpiams of intestinal worms are not very evident in 

 the average drove of hogs. Kone of the other fann animals are 

 such common hosts for intestinal worms as hogs. But it is only 

 in extreme cases of infection by intestinal worms, and in stunted 

 and poorly-cared-for hogs, that very noticeable sj-mptoms of 



