PARASITES OF ANIMALS. 341 
I may add that in fresh or well preserved specimens the 
caudal extremity of the male terminates in three conical, 
obtuse papille, from the midst of which the slender, curved 
male organ often projects ; these papilla are nearly enclosed by 
the “‘ bursa,”’ which is close to the end of the body. When 
spread out and seen from behind this has a somewhat rec- 
tangular form, being broadest laterally, each of the lateral 
expansions consisting of two small lobes united together to 
near their ends, while the intermediate odd lobe is shorter 
and scarcely prominent. Or the bursa, instead of being 
called five-lobed, as described by Diesing, might, with equal 
propriety, be described as consisting of two larger, bilobed 
lateral lobes, and a smaller intermediate lobe which is closely 
united to them. The caudal end of the female is blunt, sud- 
denly narrowing to a small, obtuse papilla-like tip, which is 
placed excentrically ; a short distance in advance of the end 
are two small, rounded, vesicle-like, lateral prominences. 
The dark, chitinous ring around the mouth is finely denticu- 
lated along its edge, and usually bears six stronger teeth, two 
of which, on opposite sides, are usually larger and stouter 
than the others, but not invariably so ; sometimes, especially 
in the larger females, they are more than twice as large as 
the rest. In some specimens I also observed two opposite pa- 
pille near the mouth, from each of which a minute, short, 
slender spine projected. The anterior end of the female is 
more obtuse than that of the male. The largest females 
from the Litchfield county pig were 1.75 inches long and .08 
to .10 of an inch in diameter. The largest males were 1.35 
long and .06 thick. 
Dr. Fletcher writes that he believes that this parasite causes 
greater pecuniary loss than any other known. He has found 
it in nine out of ten hogs examined. He also suspects that 
it may be the cause of the hog cholera. 
Some experiments undertaken by me to trace its history 
and development have not as yet thrown any light upon the 
subject. We are still in complete ignorance concerning the 
circumstances under which the eggs hatch and the abode of 
the young worms. Until such information can be obtained 
