REMOVAL OF GREEN BODIES OF HYDRA VIRIDJS. 293 



March 23. Hydras had normal green color. 



Experiment II. — March 1. Temperature 20 C. Many green 

 hydras put into a .5 per cent, solution of glycerine. 



March 1. One hydra which appeared white to the eye, but 

 which showed a single green patch of algae in one tentacle under 

 the lens, was isolated in spring water without food. 



March 18. Green color had redeveloped gradually and was 

 at this time identical with that of an ordinary hydra. 



Experiment IV. — April 16. Temperature 20 C. Many 

 green hydras put into a .5 per cent, solution of glycerine without 

 food. 



April 30. Four hydras which showed no green color under 

 the lens were isolated in spring water without food. 



May 7. The hydras showed no trace of green color under the 

 lens. Experiment discontinued. 



Experiment VIII. — May 5. Temperature 20 C. Many 

 green hydras put into a .5 per cent, solution of glycerine. Fed 

 every 72 hours with rotifers, Hydatina senta. Several formed 

 buds in the glycerine solution. 



May 24. Nine hydras which showed no trace of green color 

 under the lens were isolated in a .25 per cent, solution of glycer- 

 ine and the feeding continued. One individual had a bud 

 attached which itself was budding. None of the others had buds. 



May 26. One of the other 8 individuals was budding. 



May 27. Three of the 8 individuals were budding. 



May 29. Buds had become detached from two of the hydras. 

 Experiment discontinued. 



Experiment X. — March 12, 1907. Temperature 20 C. 

 Many green hydras were put into a .5 per cent, solution of glyc- 

 erine without food. 



March 27. Began to add food every 24 hours. 



April 7. Isolated 30 hydras which showed no trace of green 

 color under the lens in small glasses containing spring water. 



April 23. None had budded. Some had died and some were 

 developing green color. 



April 25. Fifteen hydras alive. Nine showed no trace of green 

 color under lens and six showed green patches of algae scattered 

 in various parts of the body. 



