THE ROUNDWORMS OF DOMESTIC SWINE. 



17 



. Arduenna strongy- 



Cephalic end. m., 



mouth; ph., pharynx. 

 Enlarged. (After ourit, 



1847a, PI. I, fig. 8.) 



the pharynx) running the length of the esophagus in opposite direc- 

 tions (fig. 12). 



Molin (1860b) describes the vulva as situated posteriorly, and 

 gives the following measurements: Males, 11 to 15 mm; females, 15 

 to 23 mm, which figures agree closely with the writer's measurements 

 of Arduenna strongylina. 



Schneider (1866a) reexamining Rudolphi's ma- 

 terial, gives a correct drawing of the bursa of 

 Arduenna strongylina, showing 5 pairs of papillae, / 

 of which one pair is postanal, and describes the / 

 anus as surrounded posteriorly by a crown of 

 serrated cuticular prominences (fig. 13). His 

 description, however, does not in all respects 

 agree with his drawing, as he states that there 

 are 6 pairs of papillae while the drawing shows 

 only 5 pairs. His description is also in error in 

 regard to the position of the vulva, which he TlG - ] 

 describes as directly in front of the anus. 



Von Linstow (1879b) states that the two 

 spicules measure respectively 0.72 and 0.26 mm. 

 and that the mouth is surrounded with 6 round papillae curved for- 

 ward (fig. 14). His drawing shows the pharynx with a series of 

 parallel ridges instead of a spiral. A comparison of his drawing (fig. 

 14) with the anterior end of PJiysocephalus sexalatus (fig. 15) gives 

 rise to the suspicion that Von Linstow has mistaken this species for 

 Arduenna strongylina, an opinion first expressed by Railliet and 



Henry (1911b). 



Zuern (1882 a) is the first to men- 

 tion the narrow lateral wing, extend- 

 ing longitudinally along one side of 

 the body. He describes it, however, 

 as being in a median position. As 

 has been shown, it extends along the 

 left side only. 



Stossich (1897b) states that the long 

 spicule is three times the length of the 

 short spicule, a ratio evidently derived 

 from Von Linstow's (1879b) meas- 

 urements. 



At a meeting of the Helminthological Society of Washington, the 



writer (Foster, 1911) presented a note on Spiroptera strongylina in 



which he pointed out the differences between the anatomical features 



of specimens tentatively identified by him as Spiroptera strongylina 



52865 Bull. 15812 3 



FIG. 13. Arduenna strongylina. Bursa of 

 male, ventral view, cl., cloaca; po. p., 

 postanal papillae; pr. p., preanal papillae; 

 pr. r., perianal ring. Enlarged. (After 

 Schneider, 1866a, p. 101.) 



