NEMATODE PARASITES OF BIRDS 



47 



Life history. — Unknown; probably similar to that of Syngamus 

 trachea (p. 36). 

 Distribution. — United States (Fairfax County, Virginia). 



CYATHOSTOMA COSCOROBAE Chapin, 1925 



Host. — Coscoroba coscoroba. 



L (" [ation . — Trachea. 



Morphology.— Cyathostoma (p. 41) : 



Mule 5.5 nun. long (estimated) ; anterior portion attenuate. Buc- 

 cal capsule (fig. 63) with straight sides, 83/* wide by 100/* deep; 

 lateral walls 13/* thick. Six buccal teeth, the alternate teeth (about 

 33/* high) are about twice the size of the others. Head papillae ap- 

 parently as in ('. americanum. Esophagus about 700/* long, attaining 

 its' greatest diameter (150/t) at its posterior end. Nerve ring just 



som 62 



Bigs. 61-62. — Cyathostoma americanum. 0J, Male, a, Bursa; b, 

 gubebnaculum. 62, (i , egg ; b. vulva; c, tail (female). after 

 Chapin, 1925 



anterior to middle of esophagus; position of cervical papillae and 

 excretory pore not determined. Bursa (rig. 64) well developed, 720/* 

 in transverse diameter when outspread. Ventral rays similar, slen- 

 der and approximate, about 105//, long; lateral rays parallel and con- 

 tinuous throughout their length: externo-lateral ray the shortest 

 (135/* long); medio-lateral and postero-later-aJ rays L50/t and 210/t 

 long, respectively; externo-dorsal ray 165/* long, arising near the 

 base of the main trunk of the dorsal ray, which is 150/* to its bifurca- 

 tion; branches of dorsal ray sinuous, each with 3 terminations, as in 

 ('. bronchiaZis. Spicules filiform, from 660/* to 720/* long, united at 

 tips and each bearing a finely striated wing. Gubernaculum present. 

 92/* long. 



Female about 20 mm. long. Buccal capsule (fig. 63) trapezoidal 

 in optical section, 210/* deep by 225/< wide at base, 285/t wide at apex: 

 3612- 27 5 



