304 American Fisheries Society 



narily used to contain Saratoga waters. These were in- 

 verted and a tube inserted through the stopper so that 

 the air could be withdrawn from above the surface of the 

 water. Another opening in the .stopper contained a 

 porous wooden plug which permitted the air to rise in a 

 cloud of fine bubbles, and kept the water well aerated, 

 giving it at the same time a gentle circulating motion in 

 close imitation of the natural motion of the water in na- 

 ture. All water was obtained by going out to the bay in 

 a rowboat and bringing back bottles filled with fresh sea 

 water. After the fresh water was prepared, the little 

 oysters were concentrated by the centrifugal machine 

 from the bottle that was ready to be changed and the 

 transfer made. 



A close watch was kept of the conditions of develop- 

 ment by taking a small portion of the forms when they 

 were concentrated, and placing them under the microscope. 

 It was evident at a glance whether the forms had devel- 

 oped naturally, whether they were active and in good condi- 

 tion, or whether many were dying. In this way their 

 progress was observed at every stage, from the egg to the 

 time when they became set. Abundant material also 

 was thus offered for the study of the life history of shell- 

 fish, which has been very incomplete in the past. 



In our experiment, probably a million young oysters 

 reached the stage when they began to seek their own food. 

 The first change of water was then effected and was con- 

 tinued at two-day intervals. There were naturally cumu- 

 lative losses as a result of handling and observation. 

 However, a uniformly high percentage of development 

 was secured for about two weeks. From that time on it 

 is believed that crowding tended to kill off or stunt the 

 weaker forms. Some at this period began to forge ahead 

 and develop more rapidly. Over a thousand reached the 

 setting stage, and attached themselves not only to shells 



