Schwartz: Life History of the Horse Oxyurid 



87 



according to my experience they cannot be artificially stimulated 

 to activity by heat. The worms appear rigid and without any 

 visible sign of activity, except occasional feeble movements of 

 the tail, not only after they have been removed from the host 

 but also when they are encountered in their normal location 

 within a short time after the death of the host animal. Other 

 intestinal as well as a stomach-inhabiting nematode removed 

 at the same time from the host exhibited the usual lively 

 nematoid movements of contraction, expansion, and of twisting 



the body into various positions. The only test of the vitality 

 of Oxyuris equi is close examination of the worms for evidence 

 of uterine movements, which are visible to the naked eye 

 because the internal organs can be seem through the transparent 

 cuticle. 



During the uterine contractions the eggs are pushed forward 

 and backward with the wavelike movements of the uterus and 

 this process may continue for several hours before oviposition 

 takes place. The eggs are usually liberated with considerable 

 force, often with explosive violence, and stream out through the 

 vaginal opening in stringy masses which flatten out in thin 



