116 ZOOLOGY. 
sufficient to kill the Cysticerci. Butchers especially suffer 
from tape-worms, from their habit of eating bits of raw 
meat, beef and veal harboring Cysticerci, which transform 
into species of Tenia nearly as injurious as Tenia solium.. 
As a matter of course, in the use of drugs to expel a tape- 
worm, they should be pushed so as to carry off the entire: 
animal, as new segments grow out from near the head as. 
rapidly as the proglottides are detached. 
The Cysticercus of another injurious tape-worm lives in 
the muscles and internal organs of cattle. This is the Tenia 
mediocanellata of Kiichen- 
meister, which is larger, 
with a larger darker head, 
- @ larger suckers, and with- 
out a rostrellum or hooks. 
By far the most injurious. 
species is Tenta echinococ- 
cus Siebold (Fig. 78), 
-q more frequently causing 
death than any other en- 
tozoon. In its adult or 
strobila state this worm 
only infests the dog and. 
wolf, but its larva, the 
hydatid of physicians, fre- 
quently occurs in the hu- 
man body. It is very 
small, seldom exceeding 
six millimetres in length, 
there being but four 
segments, including the 
Fig. 77.—Proglottis of 7, solium. a, testis; head, which has a pointed 
cin itt ice a encine sf somual dlosca,~ ToBtellum, with a double 
ation Denedien, crown of  large-rooted 
hooks ; there are four suckers present, and the last segment, 
when sexually mature, is as long as the anterior ones taken 
together. The hydatid (proscolex) forms large proliferous 
vesicles, in which the scolices (Echinococcus heads) are de- 
veloped by budding internally. About five thousand eggs 
