562 
Journal of Agricultural Research 
Vol. XXX, No. 6 
constricted in neck region. Buccal 
capsule heavily chitinized, 178 y in 
depth, 207 y in its greatest inside 
diameter, walls -29 y thick. Buccal 
teeth and circumoral papillae as in 
S. trachea. Esophagus about 326 y in 
length. Nerve ring? Excretory pore? 
Bursa 350 > in diameter; ventral rays 
short, stout, and approximate; lateral 
rays stout; medio-lateral ray much so; 
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 slender and parallel than postero¬ 
lateral; dorsal trunk bifurcated near 
tip, each bifurcation simple. Spicules 
short, about 49 y, similar in shape to 
those of S. trachea. 
Female.— About 7.8 mm. long, 0.65 
mm. in diameter at widest part. 
Neck region just back of buccal capsule 
about 0.35 mm. in diameter. Buccal 
capsule 300" y in depth, 440 y in aver¬ 
age diameter. Buccal teeth as in S. 
trachea. Nerve ring? Excretory pore? 
Esophagus, short and thick. Vulva in 
gravid worm dividing total length into 
ratio as 1:5.2; uterine coils extending 
backward to 1.25 mm. from apex; 
anus subterminal; tip of tail very 
blunt. Eggs 74 by 44 y, not yet 
segmented in uterus. 
Host.—Nucifraga caryocatactes. 
Habitat. —Trachea. 
Geographical distribution. —Not stat¬ 
ed for present specimens. (Host occurs 
in Europe.), 
Syntypes. —British Museum (Natural 
History), part of lot No. 92.11.4.1-3. 
One pair deposited in U. S. N. M. 
Helm. Coll., No. 26098. 
Through the kindness of H. A. 
Baylis, the author has had the oppor¬ 
tunity to study the worms upon which 
th,e foregoing description is based. 
Unfortunately, the preservation of the 
specimens is not of the best, but it is 
believed that sufficient differences can 
be made out to warrant the setting 
apart of the material from Nucifraga as 
a species distinct from S. trachea 
(Mont.). Thanks are extended to 
Baylis for securing the gift of one pair 
for the National Museum collection. 
Both of the species of Syngamus de¬ 
scribed in this paper from corvine hosts 
agree in having the dorsal ray of the 
male bursa branched, the branches 
simple. In the present species the 
branching occurs beyond the middle of 
the length. In the American form, 
S. gracilis, the bifurcation is basal, re¬ 
sulting in a total suppression of the 
common dorsal trunk. 
Syngamus gracilis n. sp. (pi. 4, figs. 38, 
40, 42). 
Syngamus trachealis Wied., (pars), Fox, 1923, 
Disease in captive wild mammals and birds 
p. 650. 
Superficially resembling S. trachea 
(Mont.), but smaller and more slender. 
Male from 3 to 3.3 mm. in length, 
cylindrical, thickness 270 y. Buccal 
capsule heavy, its wall 45 y thick; the 
diameter of the lumen of the capsule 
near the upper edge is about 200 y, the 
depth 165 y. Buccal teeth as in S. 
trachea; the largest have an altitude of 
45 y. The esophagus is nearly 600 y 
long, clavate, its greatest diameter 
135 y. Nerve ring, excretory pore, and 
cervical papillae not seen. 
Caudal bursa narrow and deep; 
branches of the dorsal ray 150 y long; 
externo-dorsal ray slightly shorter, 
measuring 132 y. The lateral rays are 
mutually contiguous, parallel, and 
about the size of either branch of the 
dorsal. The ventral rays are smaller 
and more slender. The spicules are 
distinctly unequal; the right is bent 
and measures 79 y long, while the left 
is nearly straight and is but 69 y in 
length. 
The female is from 8 to 11 mm. long 
and is proportionately stouter than the 
male. The buccal capsule is relatively 
enormous, its internal dimensions being 
525 y wide by 300 y deep. The wall is 
50 y thick. Teeth as in S. trachea. 
The esophagus is 825 y long and 225 y 
thick at the point of its greatest 
diameter, just before the esophago- 
intestinal valve. Other structures in 
the neck region not seen. The vulva 
is 1.4 mm. behind the anterior end or 
at about the anterior eighth of the 
body length. The vagina is longer 
than in related species, and both 
branches of the uterus proceed back¬ 
ward. The anus is about 300 y in front 
of the very blunt posterior extremity. 
The eggs range when mature from 79 
to 83 y in length by 40 to 46 y in 
width. 
Host. —Corvus brachyrhynchos. 
Location. —Trachea. 
Geographic distribution. —Philadel¬ 
phia Zoological Park, Nov. 14, 1914. 
Type and allotype. —-U. S. N. M 
Helm. Coll. No. 26127. Paratypes in 
collection of the Zoological Society of 
Philadelphia. 
This species is more closely related to 
S. parvus from Nucifraga caryocatactes 
than to S. trachea of the gallinaceous 
birds. Yet it is in all probability the 
form which normally occurs in the 
