702 A. Ff. Goldfarb 
ward to the amputated end. In other words, where the nerve cord 
has not yet succeeded in reaching the cut end no regeneration of 
the head occurred. ‘The following results negative such a con- 
clusion for they demonstrate that a head can be regenerated in the 
entire absence of the nerve cord. 
Head Regenerated—New Brain and Old Cord Not Connected 
The new head, made up of two or three segments, did not differ 
externally from those to be considered in the next section. 
No. 1.29. Rem ved 3 segments, 5 ganglia of the cord extracted. 
I-xamined 35 days later. 
The old cord extends anteriorly as far as the middle of the 
gth segment. ‘The regenerated cord has grown from this level 
through the 8th and almost to the anterior nd of the 7th segment. - 
The changes in the cord both old and new are exactly like those 
described in the preceding section. Segments 6, 5 and 4 contain 
not the slightest trace of a cord or nerve cell or nerve fibers, neverthe- 
less a head has formed, the number of segments of which are not 
easily made out; Fig. 20. In the head is a well-formed “brain” 
not quite separated from the ectoderm from which it has arisen 
(not clearly seen in the figure). “The ectoderm, as already described 
by other investigators, has proliferated in two directions, dorsally 
and posteriorly to form the cerebral ganglia, ventrally and pos- 
teriorly to constitute the commissures. In this particular animal 
these commissures have not grown very far, though enough to 
indicate their character and perhaps to. foretell what would have 
occurred if the animal had been allowed to live. — 
There can be no question but that the new functional head had 
developed entirely independent of the old nerve cord. 
No. 1.19. Amputated 3 segments. Removed 7 ganglia. 
‘Time, 69 days. This is substantially the same as the preceding. 
The old cord reaches to the middle of the roth segment. The 
new cord has grown forward nto part of the 8th segment. The 
anterior end of the animal, including segments 4 to 7}inclusive, 
does not have the faintest trace of any part of the cord. The 
neW head like the preceding contains cerebral ganglia and com- 
