198 NATURAL HISTORY. 



Filaria or Thread Worm resembles it closely ; mostly 

 found in horses. 



The Tape Worm (taenia lata) is composed of numer- 

 ous joints, is often twenty feet long, and instead of a 

 mouth has two canals ramifying from the suckers on the 

 head. Found in the intestines of the human species, 

 more frequently in Russia and Switzerland than in the 

 other European countries. Resembling it is 



The Solitary or Chain Worm (taenia solium), which 

 has the head provided with four tubes, and crowned with 

 double hooks ; with these they so completely absorb the 

 nourishment intended for the bodies in which they dwell, 

 that they soon exhaust them. Of all worms, they are 

 the hardest to expel. 



The Fluke (distoma hepaticum) is one inch long, four 

 to six lines broad : dull yellow or brown-gray. Its form 

 is oval, flat, with a short, bullet-shaped neck ; has on the 

 anterior portion of the body a small sucker, on the ab- 

 dominal surface a larger opening. Found frequently in 

 the gall ducts of diseased sheep and hares, but also infest 

 those of the ox, horse, or hog. 



The Qiteese (coenurus cerebralis) resembles a bladder, 

 in size about as large as a filbert or small hen's egg, in 

 which are more than a hundred little white worms, vary- 

 ing in size from half a line to two whole ones, the heads 

 of which have each four suckers. These worms are sup- 

 posed to cause the disease called the staggers, to which 

 sheep are subject. The animal appears to suffer great 

 pain, and totters round and round until exhausted. The 

 larvae gradually consume the substance of the brain, pro- 

 ducing death. Sometimes they infest the ox or other 

 ruminants ; very rarely horses. 



The Measle (cysticercus cellulosae) is barely a watery 



