76 



BULLETIN 140, UNITED STATES NATIONAL MUSEUM 



Male 4 mm. long by 300/* wide. Caudal alae regularly developed. 

 Caudal papillae number 13 pairs, arranged as follows: 3 pairs of 

 preanal papillae (1 at level of anterior and 1 at level of posterior 

 border of sucker, pedunculate; 1, sessile, just anterior to cloacal aper- 

 ture) ; 2 pairs of adanal papillae (1 pair situated externally 

 (laterally?), with long slender pedunculations, the other internally 

 (ventrally ?) with short pedunculations) ; 8 pairs of postanal papillae 

 (3 large, lateral, just posterior to cloacal aperture, 2 ventrals corre- 

 sponding to the laterals in position and, near the extremity, 3 pairs 



0-3/77/7? 



Figs. 104-107. — Heterakis bonasae. 104, Male tail, a, Ventral view ; &, 

 lateral view. 105, vulva. heterakis acdticauda. 106, male tail. 

 107, Female tail. Nos. 106-107 after Cobbold, 1861 



which vary in shape and position, some of them being absent at times, 

 or on the other hand, folds of the alae simulating additional papillae 

 above this posterior group). Preanal sucker 78/* in diameter, situ- 

 ated about 42/* from the cloacal aperture. Spicules subequal, about 

 1 mm. long, their proximal ends slightly dilated. Gubernaculum 

 absent. Cloacal aperture 160/* from caudal end, which is a slender 

 point about 71/* long. 



Female 4.2 mm. long by 400/* wide. Vulva 2 mm. from caudal 

 extremity, thus situated more or less at middle of body. Ovejector 



