THE F LATWORMS— PLATYHELMINTHES 153 



species a. latus (L. latus side; possibly refers to the two suck- 

 ers lying on either side of the scolex). 

 Genus 3. Echinococcus (Gr. cchinos, spiny; coccus, berry; refers 

 to the spiny appearance of the cyst due to the multiple 

 scoleces). 



species a. granulosus (L. granulum, grandular; the cyst ap- 

 pears to be granular). 



REVIEW QUESTIONS 



1. Distinguish between radial and bilateral symmetry. 



2. Name and locate the six directions of a bilaterally symmetrical animal. 



3. Tell how planaria changes its body shape. 



4. Describe feeding in planaria. 



5. Why are the excretory and digestive systems so extensively branched in 



planaria? 



6. Distinguish between motor and sensory nerves. 



7. Hermaphroditic animals produce both eggs and sperms yet they usually 

 have some provision for transferrence of sperms from one animal to another. What 

 biological advantage results from such exchange? 



8. Describe fission in planaria. 



9. How much power of regeneration is possessed by planaria? 



10. How can a planaria live for months without food? 



11. How do the eyes of planaria differ from the eyes of higher forms of animal 

 life such as man ? 



12. Explain how flame cells function. 



13. What do we mean when we say that planaria is a triploblastic animal? 



14. How is the Chinese liver fluke spread from one person to another? 



15. How does the life cycle of the sheep liver fluke differ from that of the 

 Chinese liver fluke? 



16. Name two ways by means of which the spread of the Chinese liver fluke 



could be stopped. 



17. Why are proglottids considered to be separate animals in certain respects? 



18. Name two ways in which the spread of the beef tapeworm can be stopped. 



19. Why must there be such a great emphasis on the reproductive systems of 

 the tapeworms? 



20. Name three tapeworms which live in man's intestine and tell how each gets 



there. 



21. How do tapeworms damage the body? 



22. When taking medicine to eliminate a tapeworm from the body, why is it 

 most important to see that the scolex is eliminated? 



23. How does Echinococcus granulosus differ from other tapeworms in its effects 

 on the human body? 



