THE AMEBIC AN NATURALIST [Vol. XLVI1I 



late on the afternoon of August 6. The next day it still 

 retained the stomach and intestine and at noon the diges- 

 tive tube was clipped off with scissors in the region of 

 the esophagus. Nothing peculiar was noted in its behavior 

 until four days later, August 11, when it discharged the 

 remainder of the digestive tube. It lived and was killed 

 at the end of eighteen days. These results are typical. 

 The animal dies unless it is itself able to eliminate all 

 organs concerned in the process of evisceration, and 

 therefore regeneration does not occur unless all these 

 organs are eliminated. 



The eviscerated animals show comparatively a low 

 degree of mortality. In an attempt to raise twenty-five 

 mutilated Thyone seven died; three of these were un- 

 able to complete the process of evisceration as described 

 above, and two more, since they lived for fourteen days, 

 probably owe their death to other causes. The sixth 

 specimen to die lived three days and had been slow in 

 eviscerating. The seventh did not receive the best of 

 care and died after three days. So considering the 

 amount of injury the mortality is extremely small where 

 proper care is taken and evisceration is complete. 



It will not be inopportune to describe the subsequent 

 behavior of the different parts after evisceration. The 

 parts expelled lie on the bottom in a more or less inactive 

 condition until they die, which happens usually in the 

 course of a few hours. At first the tentacles frequently 

 expand and contract. They are highly sensitive, as one 

 would expect, and if touched withdraw quickly into the 

 esophagus and at the same time the retractor muscles 

 will undergo strong contraction. By supporting these 

 parts near the surface of the water, so as to insure plenty 

 of oxygen, an attempt was made to keep them alive. In 

 some cases the parts remained alive for two or three 

 days, so this experiment appeared to he partially sacres> 

 ful. Death is probably due to the direct exposure of 

 tissues to the sea water and to the attacks of minute 

 organisms. The dermo-muscular portion of Thyone is 



