INTERNAL PARASITES OR WORMS. 34? 



in the large intestine, and may descend low down in the 

 rectum. 



The ova of round worms may be taken in with water, 

 etc., or may hatch within the host, as the creature is 

 termed that harbors them, possibly within the worm itself 

 in some instances. 



Fia. 31. T^ENIA SOLIUM (STONEHENGK). 

 a, head ; 6, generative orifice. 



The life-history and structure of the tape-worm is alto- 

 gether different. Every tape-worm consists of a head 

 which is usually provided with suckers, booklets, or both, 

 by which it attaches itself to the mucous covering of the 



intestines, of segments (proglottides) that are budded oil 



24 



