296 



FIRST LESSONS IN ZOOLOGY 



interior. Its body is composed of segments or serially 

 arranged parts, of which there are about 8 50 altogether. 

 It has no mouth or stomacli. It feeds simply by absorb- 

 ing into its body, through the skin, the nutritious already 

 digested food in the intestine of its host. It has no eyes 

 or other special sense-organs, nor any organ of locomo- 



233- 



I* !<;. 232. — Tmhina spiralis, cTicysted in muscle (.)f a pig. (Greatly magni- 

 fied; from specimen. ) 



I'li;. 233. — Tapeworm; head magnified, at left; whole worm may be 

 several yards long. (After Leuckart.) 



tion. Thus its body is very degenerate. The life-his- 

 tory of the tapeworm is interesting, because it lives in two 

 hosts during its life. The eggs of this parasite pass from 

 the intestine with the excreta, and to develop must be 

 taken into the body of some other animal. In the case 

 yA one of several species infesting man this second host 



