NEMATODE PARASITES OF BIRDS 



39 



SYNGAMUS PARVUS Chapin, 1925 



Host. — Nucifraga caryocatactes. 



Location. — Trachea. 



Morphology. — Syngamus (p. 34) : Similar in general shape (fig. 

 41) to S. trachea, but much smaller and differing in secondary sexual 

 characters of male. 



Male about 2.4 mm. long by 220/x, wide, cylindrical, with neck 

 region slightly constricted. Buccal capsule heavily chitinized, 178/x 

 in depth, 207^ in its greatest inside diameter; walls 29/*. thick. Buc- 

 cal teeth and circumoral papillae as in S. trachea. Esophagus about 

 326/x long; nerve ring and excretory pore not located. Bursa (fig. 

 43) 350/u. in diameter; ventral rays short, stout, and approximate; 

 lateral rays stout; medio-lateral ray very stout; externo-lateral ray 

 arising from the side of the medio-lateral; postero-lateral ray 

 slender in comparison with the other two. Externo-dorsal ray more 



Pigs. 41-43. — Syngamus parvus. 41, Outline of pair. 42, Spic- 

 ules. 43, Dorsal portion of male bursa. After Chapin, 1925 



slender and parallel than postero-lateral; dorsal trunk bifurcated 

 near tip, each bifurcation simple. Spicules (fig. 42) short, about 

 49/x, similar in shape to those of S. trachea. 



Female about 7.8 mm. long by 65Gyt maximum width; width just 

 posterior to head 350^. Buccal capsule 300^ in depth, 440^ in aver- 

 age diameter. Buccal teeth as in S. trachea; nerve ring and ex- 

 cretory pore not located. Esophagus short and thick. Vulva in 

 gravid worm dividing total length into ratio as 1:5.2; uterine coils 

 extending posteriorly to 1.25 mm. from extremity (x in fig. 41) ; 

 anus subterminal; tip of tail very blunt. Eggs 74^ by 44^, not yet 

 segmenting in uterus. 



Life history. — Unknown; probably similar to that of S. trachea 

 (p. 36). 



Distribution. — Not given. (Host occurs in Europe.) 



SYNGAMUS GRACILIS Chapin. 1925 



Synonym. — Syngamus trachealis Weidman (part), Fox, 1923. 

 Host. — Corvus brachyrhynchos. 

 Location. — Trachea. 



