558 
Vol. XXX, No. 6 
Journal o f Agricultural Research 
tempted, there is no extrusion or 
displacement of the female organs. 
The following specific names have 
been applied to members of the two 
genera but are discarded. The reason 
for discarding each name is noted. 
Syngamus bovis Willach 1896e. Railliet has stated 
(1897a) that this “species” is based on an 
artifact and not on a worm. 
Syngamus coelebs Schlotthauber 1860a. This is a 
nomen nudum, based on certain worms from 
Falco lagopus. 
Syngamus laryncheus Smit 1922. Lapsus calami for 
S. laryngeus Raill. 
Syngamus major Smit 1922. Not distinct from 
S. laryngeus Raill. 
Syngamus minor Smit 1922. S laryngeus Raill. 
renamed. 
Syngamus mucronatus Schlotthauber 1860a. 
Nomen nudum, based on worms from Picus 
canis and P. major. 
Slrongylus pictus Creplin 1849a. Syngamus trachea - 
lis Sieb. renamed. 
Syngamus primitivus Molin 1861a Fasciola trachea 
Mont, renamed. 
Syngamus pugionatus Schlotthauber 1860a. 
Nomen nudum, based on worms from Corpus 
pica and Sturnus vulgaris. 
Syngamus sclerostomum Molin 1861a. Strongylus 
variegatus Creplin renamed. 
Sclerostomum syngamus Diesing 1851a. Syngamus 
trachealis Sieb. renamed. 
Syngamus trachealis Sieb. 1836a. Fasciola trachea 
Mont, renamed. 
There remain 11 apparently valid 
species which have been assigned to 
these genera. One at least of these, 
Syngamus kingi Leiper, appears to be 
out of its usual host and may be found 
to be synonymous with a previously 
described form. Another, S. nasicola 
Linst., may prove to be equal to 
S. laryngeus Raill. 
SYNGAMUS YON SIEBOLD 
Syngamus Sieb., 1836, Arch. Naturg., (Jahrg. 2) 
1: 105-116 
Generic characters. — Strongylidae; 
sexes permanently joined in copula; 
buccal capsules of both sexes large, 
heavily walled, furnished at the base 
with eight or nine teeth arranged 
about the center, the teeth of two 
distinct sizes. Excretory pore an¬ 
terior to the esophago-intestinal junc¬ 
tion; esophagus moderate, pestle¬ 
shaped. Males with thick-walled 
bursa; bursal rays short and thick; 
spicules small to very small (150 n to 
25 p). Vulva of female in the an¬ 
terior third of the body length; tip of 
female tail blunt or acute. Eggs 
moderate in size, operculated after 
deposition. 
Habitat .—In the respiratory tract 
of birds and mammals. 
Type species .— (Syngamus trachealis 
v. Sieb.) —Fasciola trachea Mont. 
Six valid species which may be 
referred to this genus are recognized 
in this paper. The appended key 
emphasizes the points of difference. 
Two other species are considered 
doubtful and are treated at the end of 
the list. 
KEY TO SYNGAMUS 
1. Species infesting mammals_ 
Species infesting birds_ 
2. Ovarian-uterine complex reaching just 
beyond the middle of the length; spicules 
25 m long, host Bos taurus __ S. laryngeus. 
Ovarian-uterine complex reaching nearly 
to anus--- S. dispar. 
3. Branches of dorsal ray simple, not sub¬ 
divided._ 4 
Branches of dorsal ray divided in apical 
portion_ 5 
4. Spicules subequal, 50 u long, host Nucifraga 
caryocatactes _ S. parvus. 
Spicules distinctly unequal, right spicule 
79 n, left spicule 70 m long, host Corvus 
brachyrhynchos ._ S. gracilis. 
5. Each branch of dorsal ray bifurcate, spi¬ 
cules 150 p long, host Phalacrocorax 
carbo _ S. microspiculum. 
Each branch of dorsal ray trifurcate, spi¬ 
cules 60 u long, hosts gallinaceous 
birds__ S. trachea. 
Syngamus laryngeus Railliet (pl.-l, 
fig. 4; pi. 2, figs. 12, 13, 16; pi. 4, fig. 
44). 
Syngamus laryngeus Raill, 1899, Compt. Rend. 
Soc. Biol. [Paris] (XI) 1:18-21; Sheather and 
Shilston, 1920, Pusa [India] Agr. Research 
Bui. 92, 8 p. 
S. laryncheus Smit, 1922, Deut. Tierarztl. 
Wchnschr. 30: 506-507. (Lapsus for laryn¬ 
geus.) 
S. Laryncheus minor Smit, 1922, Deut. Tierarztl. 
Wchnschr. 30: 507. ( laryngeus Raill. re¬ 
named.) 
S. major Smit 922, Deut. Tierarztl. Wchnschr . 
30: 507. 
The material representing this spe¬ 
cies which is available for study 
consists of four lots, all from Bos taurus , 
as follows: One pair from Cochin 
China, received from A. Railliet in 
1899; many pairs from Manila, Philip¬ 
pine Islands, received from William 
Boynton in 1914, and two lots from 
Rio Piedras, Porto Rico, received from 
J. Bague in 1917. The specimens, a 
pair in copula, from Railliet may be 
considered in the light of type material. 
Smit described spicules reaching 
from the end of the esophagus back¬ 
ward, presumably to the bursa. It is 
uncertain just what organ has been 
mistaken for spicules; there is, however, 
no doubt that the organs described are 
not spicules. 
Six pairs have been examined in 
^detail, one from Cochin China, three 
from Manila, and two from Porto 
Rico. There appears to be consider¬ 
able variation in the actual sizes of the 
various organs, which, however, are not 
coordinated with the geographical dis¬ 
tribution. 
Male. —The total length is from 2.6 
to 3.6 mm. Sheather and Shilston 
report males as long as 5 mm. The 
buccal capsule in the Cochin China 
specimen is 0.23 by 0.27 mm.; in the 
others it is larger, attaining the size of 
(NCO 
