PARASITES OF ANIMALS. 127 
wing-like membranous expansions on each side of the head 
or anterior end of the body. The male grows to the length 
of two and one-half inches; the female sometimes becomes 
four inches long and one-twelfth in diameter. 
This worm probably propagates its kind in a manner similar 
to that of the two preceding species, and no doubt gains ad- 
mittance to the human intestine, as well as to that of the cat, 
by the medium of impure water and unclean vegetable food. 
Its effects and remedies are the same as those of the com- 
mon round-worm. 
The Round-worm of the Hog (Ascaris suilla Dujardin). 
This very closely resembles the Ascaris luwmbricoides of man, 
and probably has nearly the same habits. It differs chiefly in 
the structure of the reproductive organs. The male spicules 
are not so sharp, and the tubes of the uterus are much longer. 
The eggs are smaller. It appears to be less common than 
the Echinorhynchus gigas in the intestine of hogs, and _prob- 
ably produces less injurious effects. 
STRONGYLUS. 
The genus Strongylus includes slender, filiform worms, 
mostly of small size, and often reddish in color. Several of 
them live in the windpipe and bronchial tubes of various 
animals, including sheep, deer, cattle, pigs, etc., and when 
numerous may occasion the death of the animals that they 
infest, by suffocation. 
The body generally tapers toward the head, and sometimes 
in both directions. The mouth is small, situated at the end 
of the small head, which is either simple or with lateral ex- 
pansions. It is sometimes surrounded by small papilla, but is 
often simple, and either round or triangular, but not enclosed 
by a hard or chitinous organ, as in Sclerostoma, etc. The 
cesophagus is enlarged, club-shaped, and muscular. 
The male has the posterior end of the body provided with 
an expanded, often lobed pouch, or bursa, for adhering to the 
female during copulation. The spiculeisslender and filiform, 
enclosed in a sheath. In the female the posterior end is 
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