3. What are chromosomes? What do some zoölogists believe to be the relation between these chromosomes and heredity? 4. What are dominant and recessive characters? What is meant by "Mendel law of heredity"? 5. What is meant by the term _parthenogenesis_? What are some of its advantages and under what conditions does it take place? Name some animal in which parthenogenesis commonly takes place. 6. What is sex dimorphism? Give some examples. 7. What were the experiments of Professor Loeb and others in connection with artificially fertilized eggs? 8. How do eggs vary as to the kind of shell, amount of food, size, etc.? What is the effect of the amount of food upon the rate of development? On the stage of development at which the egg is hatched? 9. Contrast præcocial and altricial birds. 10. What is the effect of ground nesting and tree nesting upon the number of eggs and the care of the young? 11. Describe the metamorphosis of grasshopper, June beetle, honeybee, dragon-fly, cicada, may-fly, ant-lion, caddis fly. 12. Compare the development of the crayfish, crab, and lobster. What names are given to the larvæ? What is the significance in the fact that the lobster hatches in the "mysis stage"? 13. What are some of the peculiar names given to the larvæ in the case of echinoderms, worms, and mollusks? Why should these have received special names? 14. Name the three primitive germ layers. State the principal organs derived from each in the higher animals. 15. What is ontogeny? phylogeny? What is the meaning of the law "The ontogeny is an epitome of the phylogeny"? 16. Who was Weissman? What important contribution did he make to zoölogy? 17. With what phase of zoölogy is the name of T. H. Morgan associated? CHAPTER VIII POULTRY _Materials._ Either pictures or specimens of the different breeds of fowl. _General Information._ Under the term poultry are included chickens as well as turkeys, pigeons, ducks, geese, etc. Chickens are most generally raised, since they do not require such special conditions as the others. In this exercise only this form of poultry is considered. The hen has been domesticated from prehistoric times, being probably derived from the so-called jungle fowl of India (_Gallus bankiva_), which is still to be found in its native habitat. Through constant attempts to improve the domestic fowl along the lines of greater egg-production, size, etc., there have been developed a great many different breeds of fowl. These may be divided into seven groups, as follows: 1. The American Class. 2. The Asiatic Class. 3. The Mediterranean Class. 4. The English Class. 5. The Dutch Class. 6. The French Class. 7. The Ornamental and Exhibition Classes.