62 BULLETIN 140, "UNITED STATES NATIONAL MUSEUM 



Male 13.1 mm. long by 410/* wide. Tail (fig. 81) 1/57 of total 

 body length. The spicules are equal and 480//. long. The sucker is 

 190/* in diameter and has a heavily chitinized wall. There are 2 

 long-stalked papillae on each side of the sucker, 4 pairs of digitiform 

 preanal papillae (the last pair is adanal, according to Linstow's 

 figure), and 4 pairs of postanal papillae, of which the last 3 are 

 grouped close together. 



Female 14.8 mm. long by 400//. wide. The pointed tail comprises 

 1/12 of the total length. The vulva is somewhat posterior to the equa- 

 tor of the body, about 4/7 of the body length from the head. Eggs 

 62/* long by 44//, wide. 



Life history. — Probably similar to that of II. galllnae (p. 54). 



Distribution. — Europe (Germany (Koenigsburg Zoological Mu- 

 seum ) ) . 



HETERAKIS DISPAR (Schrank, 1790) Dujardin. 1845 



Synonym. — Ascaris dispar Schrank, 1790. 



Hosts. — Anas anser domestica, A. boschas, A. boschas domestica, 

 A. canadensis, A. leucopsis, A. ??ioschata, A. tadorna, Anser anser ; 

 A. cinereus, A. fabalis, A. segetum, Bernicla sandwichensis, Sumia 

 passerina, /St?*i% passerina, Tadorna tadorna. 



Location. — Cecum. 



Morphology. — Heterakis (p. 50) : White worms, thinned pos- 

 teriorly. Two lateral membranes, which are widest in the anterior 

 portion of the body and gradually narrowed posteriorly. Mouth 

 with 3 small lips. 



Male 11 to 18 mm. long. Caudal alae (fig. 82) with a sharply de- 

 limited anterior margin. Ten pairs of caudal papillae, of which 2 

 pairs are near the sucker and in relation with an anterior long bursal 

 expansion, 4 pairs of ray-like papillae and 1 pair of sessile papillae 

 are near the cloacal aperture in relation with a second shorter bursal 

 expansion, and 3 pairs posterior of these in relation with 2 smaller 

 expansions anterior of the narrow terminal tail end, according to 

 Railliet's figure ; Schneider and Fiebiger show 4 pairs in the second 

 and third groups. The 2 spicules are equal, slender and compara- 

 tively short, approximately 500//, long in American material, and 

 apparently 400//. long according to Railliet's figure. The sucker has 

 chitinous walls, interrupted on the posterior rim. 



Female 16 to 23 mm. long. Tail straight, long and slender. Vulva 

 a little posterior of the middle of the body, surrounded by a cuticulai 

 thickening. Eggs 59 to 62//, long by 39 to 41//, wide. 



Life history. — Probably similar, in a general way, to that of H. 

 gallinae (p. 54). It is less common in geese that are being ranged 

 on pasture than in those kept up and fed. 



Distribution. — United States (Nebraska), Europe (England, 

 France, Germany, Italy) and Asia (Russian Turkestan (Aulieata)). 



