Exercise 21 (Continued) 

 Embryo Development 



Total 



2. In succeeding stages of development what changes seem to take place 

 in the amount and character of albumin and yolk material. 



3. What organs are formed first? Why? 



4. When do the wings and legs first appear? 



5. When do the feather sacks first make their appearance? 



6. What is the effect of heat and cold upon the heart-beat of the embryo 

 and hence upon its development? 



7. Describe the correct position of the embryo at hatching time. 



8. Describe the process of hatching. 



9. How does an embryo, dead on the seventh day, appear before the 

 candle and upon dissection. 



10. What do you believe to be some of the possible biological causes of 

 death of the embryo during the last few days of incubation? 



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