168 SOME REACTIONS AMONG ANIMALS 



6. What peculiar habits have some crabs for self-defense ? 



7. Why are the small "water fleas," or Entomostraca, of great 

 economic importance? 



8. What is plankton ? Why is its study considered important ? 



9. What are the Entomostraca? Name some examples. 



10. Why do not crayfishes live in New England ? 



11. What is meant by ecdysis, or molting? Why must it take place 

 in the Crustacea ? 



12. What about the supposed relationship of crayfish to floods of the 

 lower Mississippi Valley ? 



Special Reports 



1. Lobster fisheries. 



2. The shrimp industry. 

 .3. The crab industry. 



4. Habits of hermit crabs. 



5. Enemies of the lobster and crayfish. 



6. The economic importance of crayfish. 



References 



Hunter, Essentials of Biology. Chap. XVIII. 



Herdman, W. A., "Our Food from the Waters." Science, p. 740, 

 Nov. 26, 1909. (Plankton.) 



Roberts, W. A., "Crab Industry of Maryland." U. S. Fisheries Re- 

 port, 1904. 



Middleton, P. H., "Saving the American Lobster." Scientific Ameri- 

 can, Oct. 16, 1909. 



Cobb, J. N., "Lobster Fishery of Maine." U. S. Fisheries Bulletin, 

 1899, Vol. XIX, pp. 241-265. 



Herrick, F. H., "American Lobster, Study of its Habits and Develop- 

 ment." U. S. Fisheries Bulletin, 1895, Vol. XV, pp. 1-252, many illus- 

 trations, 7 colored plates. 



"American Lobster, Artificial Propagation of." U. S. Fisheries Re- 

 port, 1897, pt. 23, pp. 229-238, illustrated. 



Herrick, F. H., " Lobster, Habits and Development of, and Bearing 

 upon its Artificial Propagation." U. S. Fisheries Bulletin, 1893, Vol. XIII, 

 pp. 75-86. 



Rathbun, R., " Lobsters: Transplanting to the Pacific Coast of the 

 United States." 1890. U. S. Fisheries Bulletin, 1888, pp. 453-472, illus- 

 trated. 



