EQUINE ENTOZOA. 341 



by the four conical spines surrounding the moutli, by the 

 two neck-bristles, and by the three-lobed long head of the 

 male, and by the posterior three-cleft ray having a rudi- 

 mentary or fourth branch attached to its outer edge. 



The head, when viewed in profile, is truncated, and from 

 above it is round. The body is smooth, and presents indis- 

 tinct rings. 



Development. — The eggs of the worm probably gain 

 access to the intestines of small insects, and the immature 

 form is swallowed by the horse in the water or in the 

 fodder. 



The worms then become encapsuled in the mucous mem- 

 brane of the large intestine, and are about three to six milli- 

 metres long when uncoiled. 



In this condition the sexual apparatus is not developed ; 

 and the skins are cast while the worm is still in its capsule. 



Dr. Cobbold, writing concerning the remaining history of 

 the development of these worms, says after escaping the 

 walls of the intestine, the worms re-enter the lumen of the 

 bowel to undergo another change of skin prior to acquiring 

 the adult state. They do this by rolling themselves within 

 faecal matter of the horse's intestine. In this state they 

 lie coiled up in a kind of cyst or cocoon. 



In some districts the worm is not often met with, while 

 in others it is most destructive. Mr. R Lloyd was the first 

 who recognised this worm as the cause of Welsh epizootic 

 outbreaks. 



The worm gives rise to emaciation, colic, diarrhoea, and 

 sometimes to inflammation of the bowels. 



Sometimes the intestinal pain is very acute, and the animal 

 rolls and tosses about in great agony. In other instances 

 abdominal pain is not a marked feature. 



Treatment. — A purgative should be given in the first in- 

 stance, and should be followed up by mashes, and afterwards 



