PARASITES OF ANIMALS. 121 
Spiroptera megastoma Rudolphi, of the Horse. 
This is a small species, which has a more cylindrical body, 
tapering a little toward each end. The head is separated by 
a slight constriction and bears four lobes. The mouth is 
large. The male becomes rather more than a quarter of an 
inch long, and the female nearly half an inch. It lives in 
the stomach and cesophagus of the horse and produces 
tubercles, or hard tumors, of considerable size, most frequent- 
ly situated near the pylorus. These contain many cavities, 
connected together and filled with purulent matter, in which 
there are numerous specimens of the parasite. The tumors 
are sometimes one and a half inches in diameter, and there 
are at times several in the same stomach. 
Spiroptera sanguinolenta Rudolphi, of the Dog. 
This is a larger, reddish species, which produces similar 
tumors in the cesophagus and stomach of the dog. This 
species usually grows to the length of one and a half to three 
inches, but it has been found ten inches long, living in the 
cavities of the ventricles of the heart of dogs at Shanghai, 
China, where it appears to be very common. Its complete 
history is unknown, and therefore little can be said about the 
special means of prevention, or cure. It often produces death. 
Pin-worm of the Horse (Oxyuris curvula Rudolphi). 
Figure 79. 
This is a smal], whitish worm, quite commonly found in 
the coecum and colon of the horse and ass. The female is 
about one inch and a half to two inches long, when mature. 
The male is far more rare and but one-third to two-thirds of 
an inch long. The body is fusiform, tapering to a slender 
tail, thicker in front, with the anterior end more or less 
pointed. The mouth is situated at the end, and usually has 
the form of a small, round pore, but is provided with three or 
four small retractile papillae, which can be protruded. The 
buccal cavity contains a peculiar apparatus of folds and tooth- 
like processes ; the cesophagus is long and muscular, round 
externally, but with a three-cornered cavity; it is separated 
from the round, gizzardlikeystomack by a constriction, and 
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