PROMOBPHOLOGY 99 



5. Can you assign any reason for the location of the sense organs at the anterior 

 end of the body? In a given individual? In the race to which the individual 

 belongs? (Distinguish between cause and advantage). Do you think they occur 

 here because it is anterior, or is it anterior because they occur here? 



6. Why are vehicles (made by man) bilaterally symmetrical? 



7. Express in tabular form the differences between the poles of the three axes 

 of bilateral animals, and what you can gather as to the causes of the differences. 



8. For what kind of life does bilateral symmetry fit the animal? 



9. For what kind of life does radial symmetry seem suited? Verify by illustra- 

 tions. 



10. To what extent do animals seem able to regenerate lost parts? Trace 

 out the conditions in various groups, as far as your reference library will allow. 



11. Is there any apparent limits to the numbers of metameres which animals 

 may possess? What degree of constancy or variability in this particular can you 

 discover in various individuals of the same species? 



