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H E N R I E T T E HERLANT-MEEWIS
Faulkner, 1932; Stolte, 1933; Vannini, 1947). These reports were based
essentially on histological examination; actual cell movement was not
detected. This has since been demonstrated by two methods; by counting and by the use of X-rays.
FIG. 7. Limnodrilus sp. Activation of neoblasts. E, Ectoderm; Na, Nb, Nc, different
phases of activation of neoblasts; P, parietal peritoneum; S, septum. (Krecker, 1923.)
We have used the former technique in our study on Naididae. Nais
elinguis possesses few neoblasts, but they are readily located and easily
recognized by their size. These neoblasts have been counted in worms
lacking a zone of fissiparity, in worms when this zone was rudimentary,
and in worms just a few hours after transection of the pygidium. The
number of neoblasts remained the same in the three groups but their
distribution varied. In the latter two groups there were fewer neoblasts
in the anterior segments and more near the zone of fissiparity or the
region of wound-healing : cell migration alone can explain this distribu-
H E N R I E T T E HERLANT-MEEWIS
Faulkner, 1932; Stolte, 1933; Vannini, 1947). These reports were based
essentially on histological examination; actual cell movement was not
detected. This has since been demonstrated by two methods; by counting and by the use of X-rays.
FIG. 7. Limnodrilus sp. Activation of neoblasts. E, Ectoderm; Na, Nb, Nc, different
phases of activation of neoblasts; P, parietal peritoneum; S, septum. (Krecker, 1923.)
We have used the former technique in our study on Naididae. Nais
elinguis possesses few neoblasts, but they are readily located and easily
recognized by their size. These neoblasts have been counted in worms
lacking a zone of fissiparity, in worms when this zone was rudimentary,
and in worms just a few hours after transection of the pygidium. The
number of neoblasts remained the same in the three groups but their
distribution varied. In the latter two groups there were fewer neoblasts
in the anterior segments and more near the zone of fissiparity or the
region of wound-healing : cell migration alone can explain this distribu-