PARASITES OP ANIMALS. 131 



The Strongylus of the Intestine of Sheep ( Strongylus contortus 



Eud.). 



This is a filiform species, tapering to both ends, but more 

 slender toward the head, which is provided with two semi- 

 elliptical, wing-like appendages ; the mouth with three small 

 papillse. The male is about three-fourths of an inch long, 

 with a bilobed bursa, each lobe with about eight rays ; the 

 sheath of the male spicule is very long. The female sometimes 

 becomes four inches long. 



It is not uncommon in the small intestine of sheep, but its 

 history is very imperfectly known. When abundant it may, 

 without doubt, cause serious trouble. 



Strongylus filicollis Rudolphi. 



This species also inhabits the small intestine of sheep. The 

 body is very slender and whitish or reddish. The head has 

 two, very small, lateral, wing-like appendages. The male 

 bursa is bilobed, each lobe with six rays. It is from a third 

 to four-fifths of an inch long. 



Strongylus radiatus Rudolphi. 



This worm lives in the small intestine and colon of cattle 

 and several other ruminants. The head is simple ; the mouth 

 naked. The male is about half an inch long, with a bilobed 

 caudal bursa, the lobes many rayed. The female is about 

 three-quarters of an inch long ; the genital opening is near 

 the tail. 



Its complete history is unknown. 



The Kidney-worm QEusirongylus gigas Diesing). Figure 81. 



This is the largest of all the Nematode worms, the females 

 sometimes becoming three feet long and half an inch in 

 diameter, though usually much less. The body is smooth, 

 cylindrical, tapering somewhat to each end, and more or less 

 deeply tinged with red. The head is simple, obtuse. The 

 mouth is terminal and surrounded by six rounded, chitinous 

 papillse. The male becomes ten to twelve inches long and 

 one-fourth of an inch in diameter ; the caudal bursa is cup- 

 shaped, circular and entire, without rays ; the male spicule or 



