Mar. 15, 1925 
Nematode Genera Syngamus and Cyathostoma 
563 
American crow. It is further pro¬ 
bable that S. trachea , which can hardly 
sustain itself in a host as close phvlo- 
genetically to the turkey as the dom¬ 
estic fowl is, cannot under even the 
most favorable circumstances reach 
maturity and egg production in the 
crow. From this it seems probable 
that the crow is not, as often stated, a 
reservoir for the turkey and chicken 
gape worm. 
Syngamus microspiculum Skrjabin 
(pi. 4, fig. 39). 
Syngamus microspiculum Skrjabin, 1915, Ve- 
stnik Obshch. Vet. 27: 646. 
Through the kindness of Robert J. 
Formad, the writer is able to offer the 
following translation of Skrjabin’s 
original description: 
Male. —Cylindrical in shape, dark 
brownish in color, 3.9 to 4 mm. in 
length. In the region of the posterior 
portion of the esophagus the body is 
0.29 mm. in diameter, while just before 
the bursa the diameter is 0.27 mm. 
The mouth capsule is 0.17 mm. deep 
by 0.22 mm. broad and is provided 
within at the base with three pointed 
triangular teeth, each 0.07 mm. long. 
The esophagus is 0.58 mm. long and is 
flask-shaped at its posterior end. The 
bursa of the male is very character¬ 
istic; the dorsal ray is dichotomously 
divided, the externo and postero-lateral 
rays form a compact group, and the 
latero-ventral and ventro-ventral rays 
are approximate. In this species the 
spicules are unusually characteristic. 
They are two in number, of similar 
size, and their length measures 0.15 
mm. 2 As will be seen later, no one 
species of Syngamus has such small 
spicules, and for this reason this 
organ serves as the principal diagnostic 
sign of the species. The spicules have 
a thickened base and taper toward the 
posterior end; their color is brownish. 
Female. —Length 11 mm.; diameter 
in the region of the posterior portion of 
the intestine 420 p, in the region of the 
vulva 500 p, and near the anus 250 p. 
The buccal capsule is broader than 
deep, its diameter being 250 p and its 
depth 340 p. The clavate or bottle¬ 
shaped esophagus is 765 p long. The 
vulva is situated 4.45 mm. from the 
anterior end. The eggs are 75 p long 
by 48 p in transverse diameter. Their 
shape is very characteristic. One side 
of the egg is flat, the other hemis¬ 
pherical. The tail of the worm is 
acutely conical, similar to that of S, 
variegatus Crepl. 
Syngamus microspiculum is distin¬ 
guished from all described species by 
the following: (1) Size of spicules; 
(2) there are three teeth in the buccal 
capsule; (3) the position of the vulva; 
(4) the shape of the eggs. 
Host.—Phalacrocorax carho. 
Location. —Trachea. 
Geographic distribution. —Turkestan. 
Skrjabin’s description of three buccal 
teeth would seem to demand confirma¬ 
tion. Furthermore, the statement that 
the spicules of this form are the shortest 
known in the genus is not accurate. 
At the time Skrjabin’s paper was writ¬ 
ten the spicules of S. trachea were al¬ 
ready described as 60 p in length. The 
dorsal ray of the bursa and the spicules 
are, however, ample to differentiate 
this species from any other known. 
Syngamus trachea (Montagu) (pi. 1, 
fig. 2; pi. 2, figs. 8 to 10, 18, 20). 
Wissent., 1799, Med. & Phys. Jour. [London 
2: 204-205. 
Fasciola trachea Mont., 1811, Mem. Werner. 
Nat. Hist. Soc. Edinb., (1808-10) 1: 176-193. 
Syngamus trachealis, Sieb., 1836, Arch. Naturg. 
(Jahrg. 2), 1 (1): 105-116; Ransom, 1921, U. S. 
Dept. Agr. Bui. 939, 13 p.; Ortlepp, Jour. 
Helminthology, 1: 119-140. 
Syngamus trachea (Mont.) Chapin, 1924, pres¬ 
ent paper. 
In accordance with the International 
Code of Zoological Nomenclature, the 
name of this species should be trachea 
rather than trachealis , the former hav¬ 
ing some years’ priority. 
Much stress has been laid in the past 
on the position of the vulva as a taxo¬ 
nomic character. When used with 
caution and with due consideration for 
the age of the specimen, it is of con¬ 
siderable value. However, it must be 
recognized that as the worm ages and 
the uteri become packed with eggs 
there is a stretching, not only in the 
diameter of the worm but in the 
length. For instance, in the present 
species the vulva is well forward and 
the uterine complex is largely behind 
it. In young worms, quite immature 
so far as egg production is concerned, 
the ratio of the distance from the an¬ 
terior end to the vulva to the total 
length of the worm is 1 to 3.25. In 
specimens showing a few eggs the ratio 
changes to 1 : 4.25, while in gravid 
specimens the ratio may become as 
2 In a later paper (Ann. Mus. Zool. Acad. Imp. Sci., Petrograd (1915) 1916, 20: 467-471), Skrjabin has 
redescribed this species and has given notes on certain other species of the genera considered here. The 
noteworthy difference between the two descriptions is that the spicules are described first as 150 n long, 
later as 115 ii. Either statement may be true but it is impossible to state which was the intended figure 
by a study of the context. Also in the later paper the length of the spicules of Syngamus trachealis 
(= S. trachea) is given as 0.69 mm., a figure about ten times greater than that usually accented.* This is 
undoubtedly a typographical error for 69 n. 
