202
H E N R I E T T E HERLANT-MEEWIS
~1
-
)- 5
II
V
i
V,
Control
50 H
30 min
5024 h
0
P
0 P
50H
48 h
2 2
®m
5 0 -
1
1
%
%
4 days
505 days
0
P V 1
0
P V
Number of segments regenerated
FIG. 29. Nereis diversicolor. Effect of delayed replacement therapy upon regeneration
of posterior segments in decerebrated worms. The time stated is the interval between
amputation of the segments and the transplantation or injection of a ganglion from a
cerebrate worm that had been regenerating for the same period. Controls: decerebrated
worms. The number of worms represented by each block is indicated above the block.
(Clark and Evans, 1961.)
Platynereis dumerilii, posterior regeneration was practically normal (four
segments instead of five in controls). Individuals which had undergone
posterior transection, prostomium ablation and intracoelomic graft of
the prostomium simultaneously also regenerated normally.
Recently, Durchon and Marcel (1962) working on Nereis diversicolor
verified Hauenschild's results; moreover, they have shown that transection of the nerve cord or of the peri-oesophageal ring is sufficient to
activate the brain. In Nereis, the hormone block in the brain would be
more instantaneous than in Nephtys. Durchon and Marcel also performed homograft experiments. A stump of decerebrated worm, which
does not usually regenerate, was grafted on to a normal worm and
became capable of regeneration ; if it was implanted on a posteriorly
amputated and decerebrated worm, it did not regenerate any more than
the bearer of the graft. In the first case, the hormonal influence was
H E N R I E T T E HERLANT-MEEWIS
~1
-
)- 5
II
V
i
V,
Control
50 H
30 min
5024 h
0
P
0 P
50H
48 h
2 2
®m
5 0 -
1
1
%
%
4 days
505 days
0
P V 1
0
P V
Number of segments regenerated
FIG. 29. Nereis diversicolor. Effect of delayed replacement therapy upon regeneration
of posterior segments in decerebrated worms. The time stated is the interval between
amputation of the segments and the transplantation or injection of a ganglion from a
cerebrate worm that had been regenerating for the same period. Controls: decerebrated
worms. The number of worms represented by each block is indicated above the block.
(Clark and Evans, 1961.)
Platynereis dumerilii, posterior regeneration was practically normal (four
segments instead of five in controls). Individuals which had undergone
posterior transection, prostomium ablation and intracoelomic graft of
the prostomium simultaneously also regenerated normally.
Recently, Durchon and Marcel (1962) working on Nereis diversicolor
verified Hauenschild's results; moreover, they have shown that transection of the nerve cord or of the peri-oesophageal ring is sufficient to
activate the brain. In Nereis, the hormone block in the brain would be
more instantaneous than in Nephtys. Durchon and Marcel also performed homograft experiments. A stump of decerebrated worm, which
does not usually regenerate, was grafted on to a normal worm and
became capable of regeneration ; if it was implanted on a posteriorly
amputated and decerebrated worm, it did not regenerate any more than
the bearer of the graft. In the first case, the hormonal influence was