4 
THOMPSON YATES LABORATORIES REPORT 
covered with numerous irregularly scattered papillae. There are but few species — 
found in snakes, amphibia, and eels. 
Genus Oxysoma has but three species — found in the intestines of opossums, 
frogs, and turtles. 
II. Strongylidae 
Long cylindrical body, seldom filiform or capillary. Mouth surrounded with 
papillae, probably always six in number; often has an armature of teeth or spines. 
No distinct oesophageal bulb. The male orifice at the tail end is surrounded by a 
bell-shaped bursa, with one or two spicules. The female has one or two ovaries : the 
vulva is sometimes anterior, sometimes posterior to the middle of the body, sometimes 
near the anus. Ova are already segmented or contain embryos on leaving vagina. 
Genera : Eustrongylus, Strongylus, Docbmius, Sclerostomum, Cucullanus, Syngamus, 
Pseuda/ius, OHuIanus, Oesophagostoma, and others. 
Genus Eustrongylus. Cylindrical. Mouth has no lips, but is surrounded by 
papillae. Male has a filiform spicule ; female a single ovary, vulva in anterior part 
of body. 
Only two species known : E. Gigas, which inhabits the kidney capsules of 
carnivorous animals, especially of those which eat fish — dogs, seals, etc., and 
occasionally man, horse, and deer ; and E. tubifex, found in aquatic birds — ducks, 
grebes, divers, etc. 
Life history: In case of E. gigas the eggs are eaten by fish, the larval stage 
being passed in the peritoneal cavity of some fishes. 
Genus Strongylus. Body slender ; anterior end sometimes winged. Mouth 
often indistinctly lipped, has six small papillae. Males have a conspicuous genital 
bursa, strengthened by variously arranged ridges, which are of specific value. Female 
posterior end pointed, vulva almost always in posterior half of body. 
There are numerous species found in mammals, birds, and reptiles. Some 
inhabit the intestine ; others form aneurisms in the large blood vessels, particularly of 
horses ; others live in the tracheae and lungs of sheep and cattle. They have been 
found in respiratory tract of the sheep, goat, ox, calf, pig, horse, cat, rabbit, hare, 
deer, buck, gazelle, ass, dromedary, etc. ; in alimentary tract of sheep, goat, chamois, 
ox, deer, pig, horse, rabbit, etc. ; in circulatory system of dog and horse. 
Life history: (i) Those of the digestive tract have a rhabditiform embryos 
provided with an oesophageal bulb, with three chitinous teeth. This embryo lives 
and grows on the organic matter in mud, and undergo a direct development. 
(2) Those of the respiratory tract produce larvae with an indistinct oesophageal bulb 
with no teeth ; they do not grow in mud. Their development has not been followed, 
possibly they have an intermediary host. 
8. Railliet, Traite de Zoologie Medicale et Agricole. Paris, 1895. P. 424. 
