190 PARASITOLOGY. 



mus the animal will become blind ; if the cysts devel- 

 op in the spinal cord, they produce partial or com- 

 plete paralysis of the part posterior to this point. 



Treatment, — If these cysts are located superficially 

 they may be removed by aid of a trocar or by trephin- 

 ing over the part ; as the fluid escapes from the 

 punctured cyst the mother membrane floats out and 

 by aid of a pair of forceps can be removed. 

 Taenia Serrata (Serratus — a saw). 



Synonym. — Taenia pisiformis. 



Distribution. — Found in the United States and in 

 the European countries. 



Description. — The head is only a trifle wider tham 

 the neck, and is provided with four sucker discs and a 

 rostelhim of from thirty-four to thirty-eight booklets ; 

 the first segments, Hke those in the preceding species, 

 are narrow and shorter than wide ; farther down the 

 strobilus the segments are as long as wide and 

 slightly contracted at each end, which gives the worm 

 a serrated appearance. The ripe segments are about 

 one-half inch long. 



Lite History. — The ripe segments detach them- 

 selves, pass out to the ground with the fecal matter 

 of the dog, and thus the ova become desseminated 

 over the ground, and through the food or water the 

 intermediate host becomes infested ; the intermediate 

 host is the rabbit. In the stomach of the rabbit the 

 microscopic six-hooked embryo is liberated, which 

 migrates to the peritoneal cavity and forms a cyst 

 called the cysticercus pisiformis; the cyst contains a 

 single larva or scolex (head) attached to the mother 

 membrane by means of a pedicle, and floats in a 

 colorless fluid; the dog becomes infested by eating 

 the viscera containing the encysted larva. 



