172 A GUIDE FOR THE STUDY OF ANIMALS 



2. What is gained by limiting the process of reproduc- 

 tion to special cells ? 



3. What is the difference between the appearance of 

 the nucleus of the fertilized and the unfertilized egg ? 



4. What is the advantage of cross fertilization ? How accomplished 

 in Hydra? What reason can you suggest for the sperraary's position? 



5. Describe the conjugation of a Paramecium. 



6. Describe the process of maturation and fertilization in a starfish 

 egg. 



Suggested drawings. 



a. Diving Amoeba or Paramecium. 



b. Budding Hydra. 



c. Hydra showing gonads. 



d. Starfish egg — fertilized and unfertilized. 

 Summary of important points in the study of methods of 



reproduction : — 



1 . What are the two principal methods of reproduction .' 

 How do they differ } 



2. Why is reproduction necessary } 



B. Development 



I. The Hen's Egg 



Materials. 



Hen's eggs, hydrochloric acid. 

 Definitions. 



Germ spot, a white spot, imbedded in the "yolk." This 

 is the point at which development begins. 



Yolk, the yellow portion of a bird's egg. This is a food 

 material, rich in fat. 



Albumen, the white, viscous portion of a bird's egg. 



Chalaza, the spiral portion of albumen always seen in 

 the bird's egg. 



