Law Governing Loss of Weight in Starving Cassiopea. 



71 



Table 11 shows the decline in weight of a single medusa of Cassiopea 

 xamachana starved 19 days in filtered sea- water, in the dark, at temperatures 

 ranging between 27.3° and 30.1° C, from June 30 to July 19, 191 1, at 

 Tortugas, Florida. During the first 10 days this medusa was placed in 



A medusa of Cassiopea starved 

 19 days in the dark 



3 4 5 6 7 8 



9 10 11 12 13 14 15 16 17 18 19 

 Days X 



Diagram illustrating Table ii. 



400 c.c. of sea-water which was changed once each day. After this it was 

 placed in a glass vessel holding about 6 liters and the water was changed 

 constantly by mechanical means, thus giving an abundant supply of fresh 

 sea-water. Compare this with table 12 which shows the starving rate of a 

 medusa maintained in daylight. 



Table ii. 



' According to the formula y = 44.5(1 — o.i)*. 



Remarks. — On July 19 maceration began and the experiment was discontinued. 



Table 12 shows the decline in weight of a single medusa of Cassiopea 

 xamachana starved 20 days in the diffuse daylight of the laboratory, and 

 then for 15 more days in the dark, in filtered sea-water at temperatures 

 ranging between 27.3° and 30.1° C, from June 30 to August 4, 191 1, at 

 Tortugas, Florida. During the first 10 days this medusa was placed in 400 

 t.c. of sea-water which was changed once each day. After this it was 

 placed in a glass vessel holding about 6 liters and the water was changed 

 constantly by mechanical means, thus giving an abundant supply of sea- 

 water. The conditions of the experiment are comparable with those shown 

 on table 11, excepting that table 12 applies to a medusa starved in daylight, 

 while table 1 1 shows the decline in weight of one starved in darkness. 



