236 ZOOLOGY. 



without being able to develop further. But if the 

 host is devoured by another animal, the bladder- 

 worms enter its stomach and intestine, where the 

 bladder is digested, while the tapeworm head re- 

 mains uninjured. This thrusts out its suckers and 

 attaches itself by means of them to the wall of the 

 intestine, the process of joint-formation already de- 

 scribed beginning soon afterwards. 



The following tapeworms, which are important to 

 the owner of stock, will be briefly dealt with. 



The Common or Armed Tapeworm of Man {Toenia 

 solium). 



Six to ten feet long, with seven to eight hundred 

 joints, and a circlet of hooks (Fig. 136), lives in the 

 human intestine. Several of its sexually mature 

 joints are commonly pinched off at a time, and if 

 these are picked up from a field or dung-heap by a 

 pig, the contained eggs develop into " pork measles " 

 (Gysticercus, Fig. 140), which are especially abundant in 



Fig. 140.— Measles in Fork ; tlie white spot is the head (natural size). 



the connective tissue between the muscles, and make 

 the meat " measly." They may also occur in the con- 

 nective tissue of other parts (fat, brain, spinal cord). 

 Young pigs not more than six months old are most 

 in danger of becoming measly. A tolerably large 

 number of measles can be borne very well, but if very 



