BULLETIN OF THE UNITED STATES FISH COMMISSION. 29 



the ponds and the communicating; trenches, so as to make them durable 

 and easily cared for where there is a muddy or chiyey bottom? 



3. What simple and effective devices will best serve the purpose of 

 diaphragms or filters to be placed in the sluiceways of oyster ponds as 

 filters ? 



4. To what extent will it be profitable to pre])are an extensive sys- 

 tem of connected breeding-ponds or claires in which to rear the Ameri- 

 can oyster for market? 



5. What is the most economical and successful mode of using collect- 

 ors for the purpose of rearing spat for seed or for stocking barren or 

 uncultivated waters? 



6. How thickly can oysters be planted upon a given area, say per 

 square yard, rod, or acre; and is it best to spread the planted oysters 

 evenly or irregularly over the bottom? 



7. Do embryo oysters stick to the under surfaces of collectors be- 

 cause they are freer from mud or sediment? (This is the exi)erience of 

 observers both in Europe and America.) 



8. What i^ the length of the spawning period of the American oyster, 

 and in what month does spat first appear, and when does it cease to fall 

 or set in the autumn? 



9. What is the minimum of time in which an oyster is matured, count- 

 ing from the time it was spawned until it is of marketable size? 



10. Do oysters \ary very greatly in the rapidity of their growth in 

 different localities? 



11. What is the cause of the variation in the quality or flavor of oys- 

 ters from different localities? 



12. What forms of microscopical organisms are the most frequently 

 met with in the stomachs of oysters, and therefore the most valuable 

 food of the animal? 



13. What is the average density of the water in which oysters will 

 always thrive best? 



14. What temi^eratures are most favorable to their growth ? 



15. What temperatures are most hurtful, and under what circum- 

 stances ? 



16. What means of oxygenating the water in oyster ponds are the 

 most satisfactory? 



17. What parasites and enemies of the oyster are most hurtful, and 

 in what way ? 



Some of these queries we have, in different publications issued during 

 the past two years, sought to answer approximately, but it will be seen 

 that many of them would require an elaborate series of investigations 

 to be carried out before it would be possible to give entirely satisfactory 

 replies. It is much easier to ask questions than to answer them, but 

 there is no easier way to find out how little we really know than to ask 

 a series of questions such as the above. It will doubtless require many 



