GENERAL REVIEW TOPICS. 169 



19. What different kinds of covering have animals? 



20^ What is meant by metamorphosis ? 



21. What are the principal groups in classification? 



22. What is von Baer's Principle? 



23. What is meant by Natural Selection? 



24. What is meant by The Survival of the Fittest? 



25. What animals are useful to man? 



26. What animals are injurious to man? 



27. State the rules for naming animals. 



28. What methods of reproduction have you found? 



29. What is parthenogenesis? What is hermaph- 



roditism ? 



