336 AN INTRODUCTION TO THE STUDY OF FOSSILS 



3. Compare in general the composition of a bone with that 

 of a clam or oyster shell. 



4. Give two causes of variation in the total number of bones 

 in the cat. 



5. Compare the arrangement of the ribs in the cat with that 

 in fish and snakes. 



6. What evidence does the cat show in its development that 

 its ancestors possessed a larger number of ribs ? 



7. Compare the elongation of the neck of the giraffe with that 

 of the swan. 



8. How are the fore limbs attached to the trunk? The 

 hind limbs ? 



9. In what groups of vertebrates is the clavicle well de- 

 veloped? In what vestigial or entirely wanting? Account 

 for this difference. 



10. What does the condition of the clavicle in the cat indicate 

 as to its past history? 



11. Of what significance are the vestigial hip bones in the 

 Sirenia and Cetacea ? 



12. What is the primitive number of digits in a mammal? 

 Note variations from this. 



13. What is the function of joints? How can you note their 

 presence in fossils ? 



14. Distinguish between voluntary and involuntary muscles. 

 Give examples of each. 



15. Given the bones of an extinct vertebrate, how can you 

 estimate its shape when living ? 



16. Describe briefly the digestion and assimilation of the cat's 

 food from its capture to its use by the millions of individual 

 cells. 



17. Enumerate the cat's teeth with the special function of 

 each group. What special tooth distinguishes the Carnivora, 

 both recent and fossil ? 



18. How many sets of teeth does a cat have ? 



19. Give an example of change of function in teeth ; of 

 reduction in numbers. 



20. Describe briefly the course of the blood through the circu- 

 latory system. 



21. What element is necessary to the freeing of the energy 

 and heat stored up in the food ? 



22. Describe the ])rocurement of oxygen by the living body. 



23. How is voice produced ? 



