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 papillae, from the midst of which the slender, curved 

 male organ often projects ; these papillae are nearly enclosed by 

 the " bursa," wliich 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 tlieir ends, while the intermediate odd lobe is shorter 

 and scarcely prominent. Or the bursa, instead of being 

 called fivc-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 

 tlian the others, but not invariably so ; sometimes, especially 

 in the larger females, they are more than twice as large as 

 tli^rest. In some specimens I also observed two opposite pa- 

 pillae 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 



