THE ROUNDWORMS OP DOMESTIC SWINE. 



15 



FIG. 9. Arduenna ttrongylina. Cross section 

 through body of female in the region of the 

 vulva. bd. w., body wall; cut., cuticle; ., 

 eggs; int., intestine; tit., uterus; v., vulva; 

 va., vagina. Enlarged. ( After Ciurea, 1911. 

 Text fig. 1, p. 131.) 



of the vulva, and in cross section it was seen that the same material 



filled the terminus of the vagina. This material was not seen in 



any of the specimens examined by the present writer. 1 



The vagina (fig. 5) extends first transversely under the uteri and 



intestine; then leading above these organs it continues posteriorly 



and parallel with the intestine (except 



for an S-shaped bend near its middle) 



along the right side until it reaches 



the junction of the uteri. 



One of the uteri, commencing at the 



end of the vagina, extends posteriorly 



and dorsally without convolutions 



(except for an S-shaped bend 875 // 



from its vaginal end) until it reaches 



a point 3.6 mm. from its union with 



the vagina. 

 Here it makes 

 an abrupt 

 turn, runs 

 back anteri- 

 orly and ven- 

 trally, paral- 

 lel with its dorsal limb, until its outline is 

 lost to view beneath the mass of eggs distend- 

 ing both uteri and filling the body cavity 

 from the end of the esophagus to within a 

 short distance of the anus, greatly obscuring 

 the outlines of the organs. Throughout its 

 visible length this uterus is of nearly uniform 

 diameter, about 95 fi. The distal ends of the 

 two uteri are at opposite extremities of the 

 worm; the uterus that first extends poste- 

 riorly ends anteriorly at a point 613 fi anterior 

 of the base of the esophagus in a long con- 

 voluted ovary crowded into the narrow space 

 between the esophagus and the lateral mus- 

 cular wall. The other uterus, running in a 

 similar but reverse direction from the uterus 



just described, turns first anteriorly for about 3.5 mm., then posteriorly, 



ending at a point about 875 fj. from the tip of the tail. The diameter 



of the posterior uterus, like that of the anterior uterus, is nearly 



i Such a secretion is not, however, uncommon among nematodes. The writer has collected many speci- 

 mens of (Esophagostomum columbianum the vulva of which was closed by a plug of dark-red secretion 

 Insoluble in alcohol but which could easily be removed by a needle. Specimens of this parasite have been 

 observed so firmly welded in copulation that hot alcohol did not cause their separation and they yielded 

 only to forcible traction with a needle or forceps. 



FIG. 10. Arduenna strongylina. 

 General view of body of male 

 from right side, b., bursa. X 7. 

 (Original.) 



