Contents 



Part I. Aids to recognition of Fresh-water Organisms. Page 



Insects 5 



Crustaceans 36 



Molluscs 38 



Plancton 40 



Other lesser Invertebrates 41 



(See also Finding List on next page.) 



Part II. A Program of class work in Fresh-water Biology. 



Collecting methods and apparatus 64 



Equipment 66 



Practical Exercises: 



A. Land-and-water studies: 



1. Local hydrography. . . '. 67 



2. The local water supply 68 



3. A pond 68 



4. A stream 69 



5. A lake 70 



6. A marsh 70 



B. Association sttidies: 



7. The life of a pond 71 



8. The life of a rapid stream 73 



9. The life of a slow stream 74 



10. The life of a lake bottom with muddy shores 75 



11. The life of a flood-plain marsh 76 



12. The life of an upland swamp or bog 77 



13. The life of rock ledges in a stream bed 78 



14. The life of a spring brook 79 



15. The "blanket algae" association 80 



16. Plancton 81 



C. Adjustment studies: 



17. Hibernating devices of fresh- water animals 82 



18. Reproductive methods of fresh- water mussels 82 



19. A laboratory study of the gills of insects 83 



D. Economic studies: 



20. The fish-forage of a water meadow (partly quantitative) 85 



21. A study of fish food (partly quantitative) 85 



E. Demonstrations: 



22. The efiiciency of stream-line form 86 



23. The relation between fecundity and nurture in fishes 87 



24. Apparatus and methods for quantitative study of plancton 88 



25. Fish-cultural methods 88 



