538 
It was noticed, March 11, that regeneration had begun to take place 
at the anterior end of the graft. After a few weeks, the piece 
seemed to have stopped growing and it was killed, April 22. 
Drawings of the dorsal, lateral and ventral sides of the anterior 
end of the worm are given in figs. 1, 2 and 3 respectively, in which 
Higa. 
the grafted segments are shown by stippling. The segments are 
numbered at the side, indicating their position in the worms used in 
the experiment. The regenerated part is composed of two segments, 
which are considerably smaller than the segments from which they 
arose. The resemblance of the anterior segments to a normal head 
possessing a mouth and prostomium is evident. 
The anterior end of the worm was sectioned longitudinally in a 
dorso-ventral plane. The union of the graft and the larger com- 
ponent is so complete that it is only by careful study of the sections 
that the place of union can be determined. The ectoderm and the 
walls of the digestive tract of one piece are continuous with the cor- 
responding part of the other piece. The only indication of union shown 
by the nervous system is a slight bend in the ventral nerve cord. 
