12 



THE ROUNDWORMS OF DOMESTIC SWINE. 



extending in a generally posterior direction, joining the uteri at a point about 1.1 mm. 

 from the vulva measured in a straight line (fig. 5;. 



Eggs oval, 34 to 39 /i long by 20 ft wide, with thick shells. Embryos well developed 

 in the shell before oviposition (fig. 6). 



HOSTS. Domestic hog (Sus scrofa domestica), wild boar (Sus scrofafera). 



LOCATION. Stomach and small intestine. 



LOCALITIES COLLECTED. United States: Bethesda, Md.; Benning, D. C.; Chicago, 

 111.; South Omaha, Nebr.; St. Louis, Mo.; Kansas City, Mo.; Denver, Colo.; Brazoa 



Lsa :_=. 



Homm. 



FIG. 3. Arduenna strongylina. Posterior end of 

 body of male, viewed from right side. I. sp. , long 

 spicule; s. sp., short spicule. X 65. (Original.) 



County, Tex. Europe: Germany, 

 France, Hungary, Roumania, Italy. 

 Asia: Turkestan, Indo-China. 



The number of spiral ridges 

 in the pharynx seems to vary 

 both with the sex and among 

 different individuals of the same 

 sex. In the specimen figured, a 



Ho mm. 



FIG. 4. Arduenna strongylina. Posterior end of 

 body of female, viewed from left side. a. , anus; 

 ov., ovary; p. ut., posterior uterus; red., rectum; 

 ter. p., terminal papilla. X 150. (Original.) 



female (fig. 1), there are four separate ridges, the usual number for 

 females. Males have, as a rule, but three spirals. Kailliet and Henry 

 (191 Ib) mention 2 to 3 spiral ridges for males and 4 to 5 for females. 

 The retractor muscles controlling the movements of the right 

 spicule are a pair of narrow lamellar strips, longitudinally finely 

 striated, asymmetrically twisted in the center, attached at the pos- 

 terior end to the spicule and at the anterior end to the ventral side 



