THE ROUNDWORMS OF DOMESTIC SWINE. 



13 



//7/1 



of the body. The muscles are fullv as long as the spicule they control 

 (fig. 7). 



The vas deferens appears as a tube of darker color than the intes- 

 tine, about 130 fjL in its average diameter, and extending throughout 

 the posterior third of the body length. About 450 p from its ter- 

 minus it rapidly diminishes in diameter toward the cloaca, and in 

 the specimen figured (fig. 8) is bent in 

 the shape of the letter S. The seminal 

 tube is very long and convoluted, re- 

 sembling in appearance the ovaries of 

 the female. Near the posterior end of 

 the male the intestine, 123 // wide, first 

 crosses above the vas deferens toward 

 the dorsum, then curves underneath as 

 it approaches the cloaca. Its terminus 

 was obscured by the organs lying above 

 it. In the specimen figured (fig. 8) the 

 sheath of the right spicule is much con- 

 tracted and appears as a dark-colored 

 bag too short to contain the entire 

 spicule and within which the base of 



the spicule 



may be 



dimly 



seen. The 



ventral 



surface of 



the male 



-in the re- 

 gion im- 

 mediately 



anterior of 



the bursa 



is f u r - 



nished with 7 to 8 parallel longitudinal 



, , cuticular ridges divided transversely 



IQjuL. into serrations. This structure, modi- 



FIQ. 6,Arduenna strongylina. Lateral fications of which are seen in many 



view of egg removed from a ruptured ne matodes. including PTimOCephdluS 

 uterus, o. c., albuminous covering; . . 



emb., embryo; sh., sheii. x 1,450. sexalatiLS, probably assists in maintain- 

 ing the position of the male in copula- 

 tion, as suggested by Ciurea (1911). The anus is partially encircled 

 by a rim of thickened cuticle, the outer edge of which is ornamented 

 with serrated cuticular projections. This cuticular thickening 

 extends along the posterior and left sides of the anus, forming about 



6. 



FIG. 5. Arduenna strongylina. Ventral 

 view of middle of body of female, a. tit., 

 anterior uterus; int., intestine; j. ut., 

 junction of the uteri; I. c. w.', lateral 

 cuticular wing; p. ut., posterior uterus; 

 v. vulva; va., vagina. X 58. (Original.) 



