130 PARASITOLOGY. 



was not distended and the coagulum, was slightly 

 larger than a pea and contained three worms. One 

 proved to be a Triodontophorus serratus, the posterior 

 extremity of which is illustrated in figure 21, Plate 10. 

 The large intestines of this young horse contained 

 only two species, those of the Triodontophorus serra- 

 tus and the Sclerostomum vulgare. All other worms 

 examined up to this time for classification from throm- 

 bi and aneurisms have proven to be the Sclerostomum 

 equinum. (Strongylus armatus.) One investigator 

 has ventured the opinion that this latter parasite prob- 

 ably passes its larval stage in the abdominal blood 

 vessels. 



Thrombosis and Embolism. 



In those vessels containing small thrombi and which 

 must be regarded as rather recent invasions there is 

 noted an endarteritis with possibly some destruction 

 of the endothelium. Later stages show atheromatous 

 changes and in old aneurisms even areas of calcifica- 

 tion. The middle coat shows hypertrophy and inflam- 

 matory processes. The outer coat shows connective 

 tissue proliferation. 



A vessel wall thus diseased may give way to a more 

 or less extent and sacculation occurs. The aneurism 

 now developed may ibe saccular, fusiform or cylin- 

 droid. On the inner side will be found a mass of 

 coagulum adhering closely to the degenerating vessel 

 wall. The larvae may be found in the coagulum with 

 one end extending out into the blood stream or lodged 

 in the walls between the coats or penetrating partially 

 protruding on either side of the vessel wall. 



