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 oesophagus 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 oesophagus 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 small, 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 oesophagus is long and muscular, round 

 externally, but with a three-cornered cavity ; it is separated 

 from the round, gizzard-like stomach by a constriction, and 

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