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.—lf 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 than 
the neck, andis provided with four sucker discs and a 
rostellum of from thirty-four to thirty-eight hooklets ; 
the first segments, like 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 
aserrated 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. 
