REGENERATION IN A TROPICAL EARTHWORM. 



355 



warrant a statement that total replacement of lost segments can- 

 not take place posteriorly. It should be noted that when eighteen 

 or more segments were amputated the digestive organs including 

 part of the intestine which begins in the region of segment fifteen, 

 as well as all of the reproductive organs were removed. When 

 the cut was made between 17/18 and 24/25 twelve to sixteen seg- 

 ments usually regenerated. Posterior to 24/25 ten to fifteen seg- 

 ments regenerated. The posterior limit of anterior regeneration 

 by tail pieces has not been determined, but it certainly lies un- 

 usually far back for earthworms, and at least in the last third of 



the length of the worm. 



TABLE I. 



SERIES Two. 

 Anterior Ends from One to Twenty Segments Removed. 



85 worms were amputated. 



Si worms survived operation. 



48 worms regenerated exact number of segments lost. 



27 worms regenerated a smaller number. 



5 worms regenerated a larger number. 



i worm failed to regenerate. 



Table I. summarizes briefly the results obtained from a char- 

 acteristic series of operations. Table II. summarizes the regen- 

 eration in the region lying between segments six and eighteen 



TABLE II. 



SERIES Two. 



Results of Operations betzvecn Intersegmental Furrows 5/6 and 17/18. 



