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H E N R I E T T E HERLANT-MEEWIS
1961). Such cells have been described for all worm groups—in Nematoda
(Gersch and Scheffel, 1958) and Trematoda (Ude, 1962) as well in
Turbellaria (Lender and Klein, 1961). They have been described in
Annelida: in leeches by Hagadorn (1958, 1962), in polychaetes by
Scharrer (1936), Schaefer (1939) and more recently by Bobin and
Durchon (1953), Arvy (1954), Durchon and Frezal (1955), Defretin
(1955, 1956), Hauenschild (1959), Clark and Clark (1959), Clark and
Bonney (1960), Durchon (1960), Herlant-Meewis and Van Damme
(1962a, b). In terricolous oligochaetes, they have been observed by
Scharrer (1936), Harms (1948), Herlant-Meewis (1955), Brandenburg
(1956), Michon and Alaphilippe (1959), Deuse-Zimmerman (1960),
Otremba (1961), Aros and Vigh (1962), Juberthie and Mestrov (1962).
The mechanism of granule synthesis is the same as in all glandular
cells. This has been clearly shown by electron microscopy by Stiennon
and Drochmans (1961) in Phasmidae, by Bern et ah (1961) and Hagadorn et ah (1963) in Hirudinae, and by Röhlich et ah (1962) in Oligochaetae. In Lumbricus, Scharrer and Brown (1961) showed how the
granules arise from the ergastoplasm and evolve in contact with the
Golgi apparatus. The release of granules into the blood stream through
the capillary network has been demonstrated using the same technique
(DeRobertis, 1961).
The exact nature of these secretions is not yet known, but it is
probably highly complex. Chromatographie separation of neurohormones from extracts of different regions of the nervous systems of
insects and crustaceans has revealed two neurohormones, D and C, which
act as antagonists on heart function and on chromatophores. Recently,
Gersch et ah (1957) isolated and crystallized these substances which do
not seem to be associated with adrenaline or its derivatives. They
apparently contain no lipoids, stéarines or phosphatides, but are
characterized by an ester bond. The C factor is basic, while neurohormone D is acid. In Eisenia foetida we have observed transitional
stages between basicity and acidity in the same cells and put forward
the hypothesis that this property of the substance must change during
synthesis (Herlant-Meewis, 1955).
We have as yet little information on the localization of neurosecretory
cells participating in regeneration phenomena. Only a few histological
observations have been made. Clark and Bonney (1960) have described
neurosecretory cells in Nereis diversicolor sited in front and behind the
cerebral ganglia. Only those of ganglion 4, which is anterior, seem to be
more active during the first 2 days of caudal regeneration. I n Nephtys,
according to Clark (1958, 1959) neurosecretory cells are present in all the
ganglionic nuclei of the cerebral ganglion except in the corpora pedunculata and the nuchal nuclei. Clark and Clark (1959) showed that the
H E N R I E T T E HERLANT-MEEWIS
1961). Such cells have been described for all worm groups—in Nematoda
(Gersch and Scheffel, 1958) and Trematoda (Ude, 1962) as well in
Turbellaria (Lender and Klein, 1961). They have been described in
Annelida: in leeches by Hagadorn (1958, 1962), in polychaetes by
Scharrer (1936), Schaefer (1939) and more recently by Bobin and
Durchon (1953), Arvy (1954), Durchon and Frezal (1955), Defretin
(1955, 1956), Hauenschild (1959), Clark and Clark (1959), Clark and
Bonney (1960), Durchon (1960), Herlant-Meewis and Van Damme
(1962a, b). In terricolous oligochaetes, they have been observed by
Scharrer (1936), Harms (1948), Herlant-Meewis (1955), Brandenburg
(1956), Michon and Alaphilippe (1959), Deuse-Zimmerman (1960),
Otremba (1961), Aros and Vigh (1962), Juberthie and Mestrov (1962).
The mechanism of granule synthesis is the same as in all glandular
cells. This has been clearly shown by electron microscopy by Stiennon
and Drochmans (1961) in Phasmidae, by Bern et ah (1961) and Hagadorn et ah (1963) in Hirudinae, and by Röhlich et ah (1962) in Oligochaetae. In Lumbricus, Scharrer and Brown (1961) showed how the
granules arise from the ergastoplasm and evolve in contact with the
Golgi apparatus. The release of granules into the blood stream through
the capillary network has been demonstrated using the same technique
(DeRobertis, 1961).
The exact nature of these secretions is not yet known, but it is
probably highly complex. Chromatographie separation of neurohormones from extracts of different regions of the nervous systems of
insects and crustaceans has revealed two neurohormones, D and C, which
act as antagonists on heart function and on chromatophores. Recently,
Gersch et ah (1957) isolated and crystallized these substances which do
not seem to be associated with adrenaline or its derivatives. They
apparently contain no lipoids, stéarines or phosphatides, but are
characterized by an ester bond. The C factor is basic, while neurohormone D is acid. In Eisenia foetida we have observed transitional
stages between basicity and acidity in the same cells and put forward
the hypothesis that this property of the substance must change during
synthesis (Herlant-Meewis, 1955).
We have as yet little information on the localization of neurosecretory
cells participating in regeneration phenomena. Only a few histological
observations have been made. Clark and Bonney (1960) have described
neurosecretory cells in Nereis diversicolor sited in front and behind the
cerebral ganglia. Only those of ganglion 4, which is anterior, seem to be
more active during the first 2 days of caudal regeneration. I n Nephtys,
according to Clark (1958, 1959) neurosecretory cells are present in all the
ganglionic nuclei of the cerebral ganglion except in the corpora pedunculata and the nuchal nuclei. Clark and Clark (1959) showed that the