246 PARASITES OF THE DOMESTIC ANIMALS 



setting up proliferative changes with the formation of prominences. 

 Outwardly the tumors are limited by the muscular layers of the stom- 

 ach, the connective tissue involved being that of the submucosa. In 

 old tumors the walls become of a dense fibrous character, taking some- 

 what the consistency of cartilage. In these no worms may be found, or 

 there may be a few of their disintegrated bodies contained in a small 

 amount of purulent material. 



Essentially the presence of such parasites can only be revealed post- 

 mortem. The tumors are not as a rule numerous, and do not seem to 

 cause any serious disturbance. 



The manner of infestation by the worms is not known, nor is it known 

 whether they multiply within the tumors. 



3. Habronema microstoma (Spiroptera microstoma). Filariidse 

 (p. 244). — This species is larger than the preceding and may also be dis- 

 tinguished from it by the absence of the constriction behind the cephalic 

 extremity. The mouth presents a notch on each side, and there are two 

 lateral lips. The tail of the male is rolled spirally, has two lateral wings, 

 and a varying number of papillse. There are two spicules. The vulva 

 of the female is situated near the anterior third of the body. 



Length of female, 12-27 mm. (1/2-1 inch); male, 10-20 mm. (3/8-3/4 

 of an inch). 



The eggs are elongate and truncated at their extremities. They are 

 45-49 microns long by 16 microns wide. Development and hatching 

 are within the body of the female (o vo viviparous) . The hberated em- 

 bryos measure 90-98 microns in length. 



The life history is not known. 



Occurrence. — Post-morten inspection of the interior of the horse's 

 stomach will occasionally reveal the presence of these worms in such 

 quantity as to cause an undulating movement of the contents of the 

 organ, due to their active motion. While most of the worms are free, 

 many may be found with their heads inserted in the gastric crypts of 

 the right sac. More or less inflammatory disturbance of the mucosa 

 may thus be set up, in some cases involving ulceration. 



As in the case of the preceding species, infestation with these worms 

 can only be revealed when they are brought to light after the death of 

 the host. Where a chronic gastric disturbance is suspected to be due 

 to parasites of the stomach, one or two ounces of oil of turpentine may 

 be given in two or three pints of linseed oil. 



FiLARiiD^ OF Sheep and Cattle 



1. Gongylonema scutata (Spiroptera scutata). Fig. 128. Filariidse 

 (p. 244). — The body is long and filiform, white or yellowish white, 

 striated transversely^, and slightly attenuated toward the extremities. 



