566 S. MorgiiUs 



those obtained from my experiment, would result, and would also 

 very likely remain dwarf worms. 



If my view in regard to the formation of dwarf worms from 

 pieces of Lumbriculus is true, the worms if divided would become 

 continually smaller and smaller, till they would be reduced to 

 single segments. 



As a result o-f the continual cutting off of the regenerated tissue 

 more new material was produced than when only one cut was 

 made through the same level. Thus in the first experiment for 

 the third period of two weeks there were to each old segment 0.5- 

 0.8 of a new segment, while the pieces cut only once did not produce 

 even a single segment for the same length of time. 



C Regeneration of Regenerated Parts 



Tails that had been regenerating from parts of Lumbriculi for 

 some time, were cut off so that none of the old tissue remained. 

 Some of the tails had been regenerating for two weeks. After 

 removal from the old part a new tail was allowed to regenerate in 

 course of the following two weeks. These were also cut off. 



a October 31. Thirty such regenerated tails were obtained 

 from pieces belonging to the third level, and thirty regenerated 

 tails from pieces of the fifth level, of worms that were divided into 

 eight parts each. These tails had been regenerating since October 

 17. The tails regenerated by pieces of the third level we will call 

 for convenience A, and those regenerated by pieces of the fifth 

 level B. 



These sixty tails were kept for two weeks, and when examined 

 on November 14, eighteen A tails and thirteen B tails, or half 

 the original number were alive. Those that survived regenerated 

 new heads of five to seven segments, with one exception, of which 

 I shall speak presently. The little worms contained on an average, 

 probably, about forty-five to fifty-five small segments. 



In the course of tivo following weeks they did not produce any new 

 posterior segments. That this is really so can be ascertained with 

 certainty because in the regenerating tails the terminal five to six 

 segments, which are the youngest, are microscopical in size. Dur- 



