380 



BULLETIN 140, UNITED STATES NATIONAL MUSEUM 



he named Wedl's species may not be identical with it, as he thought 

 (see H. wedli, p. 381) does not alter the status of H. wedli as that is 

 the name given to Wedl's species. 



Hosts. — Primary : Numenius arquatus, Querquedula circia; sec- 

 ondary: Probably fish, according to Jaegerskiold. 



Location. — Esophagus. 



Morphology. — Hystriohis (p. 375) : Body long and slender. Mouth 

 opening small, triangular, surrounded by 6 small papillae, wart- 

 shaped with small points. Head (fig. 441a) with closely-set spines, 

 larger than those found on anterior cervical region. Largest spines 



ng$m 







Figs. 440-441. — 440, Hystbichis cygni, Head end. After Molin, 1861. 441, 

 Hystbichis neglectus. a, Head end ; b, male tail ; c, female tail ; d, egg. 

 Aftek Jaegerskiold, 1909 



40 to 50/a long by 20/* wide. Spines extend along body for distance 

 of 1.5 mm. 



M ale specimens imperfect; length more than 33 mm. Bursal cup 

 (fig. 4415) not prominent, scarcely wider than the portion of body 

 preceding it, of thick muscle, the hollow inner part shallow. An- 

 terior to this on each side of body a row of papillalike structures, 

 12 or more in number. 



Female about 111 mm. long; maximum width 1.5 mm., width at 

 head end 450 to 500^, at tail end (fig. 441<?) 350/x. Each circle of 

 the head contains 55 to 57 spines. Esophagus 8.25 mm. long. Eggs 

 79 to 84/a long by 42 to 44/x wide, with large but not closely-set pit- 

 tings (fig. 441a*). Shell about 4.5^, thick; poles rounded. 



