EGG CORTEX IN MORPHOGENESIS
387
(b) During the first hours of development, i.e. before the appearance of grey (or clear) crescent, bilateral symmetry is
prepared by some topographical changes in the relations of
yolk to the cortex, which remains temporarily unchanged.
(c) After the 'cortical reaction of symmetrization' which happens
when the grey crescent is formed, a cortical reorganization
leads to the formation of a dorso-ventral cortical field.
(d) Although rather fixed, the cortical field may be altered—
partially — by some modifications of its relations to the yolk
or by stretching.
(e) The morphogenetic role of the cortex has been demonstrated
by grafting experiments.
(f ) Morphogenesis is induced by an interaction between cortical
field and inner yolk.
(g) The period between the one and the 8-cell stages must be
considered as being a critical one with regard to this
interaction.
(h) The cortical field may be considered in terms of differences in
permeability.
2. (a) Structural and ultrastructural differences between dorsal and
ventral cortex are still unknown.
(b) Difference in permeability to certain dyes ought to be
extended to physiological factors.
(c) The nature of the hypothetical interaction between cortex
and yolk should be investigated.
Acknowledgements
We express our warmest thanks to Profs. A. Dalcq and J. Mulnard
who read the manuscript and considerably improved the English.
References
Ancel, P. and Vintemberger, P. (1948). Bull, biol., Suppl. 31, 1.
Born, G. (1885). Arch. mikr. Anat. 24, 475-545.
Brächet, A. (1904). Arch. Biol. 21, 103.
Chambers, R. (1918). Proc.Soc. exp. biol., N.Y. 17, 41.
Curtis, A. S. G. (1960). J. Embryol. exp. Morph. 8, 163.
Curtis, A. S. G. (1962). J. Embryol. exp. Morph. 10, 231.
Dalcq, A. (1941). 'L'œuf et son dynamisme organisateur', 580 pp. Albin Michel,
Paris.
Dalcq, A. and Dollander, A. (1948). C. R. Soc. Biol., Paris 142, 1307.
Dalcq, A. and Pasteels, J. (1937). Arch. Biol. 48, 669.
Dalcq, A. and Pasteels, J. (1938). Bull. Acad. roy. Belg. 3, 261.
DoUander, A. (1950). Arch. Biol. 61, 1.
Dollander, A. (1952). C. R. Ass. Anat., 38ème Réun. Nancy, 430.
Dollander, A. (1952). C. R. Soc. Biol. Paris 146 1607
387
(b) During the first hours of development, i.e. before the appearance of grey (or clear) crescent, bilateral symmetry is
prepared by some topographical changes in the relations of
yolk to the cortex, which remains temporarily unchanged.
(c) After the 'cortical reaction of symmetrization' which happens
when the grey crescent is formed, a cortical reorganization
leads to the formation of a dorso-ventral cortical field.
(d) Although rather fixed, the cortical field may be altered—
partially — by some modifications of its relations to the yolk
or by stretching.
(e) The morphogenetic role of the cortex has been demonstrated
by grafting experiments.
(f ) Morphogenesis is induced by an interaction between cortical
field and inner yolk.
(g) The period between the one and the 8-cell stages must be
considered as being a critical one with regard to this
interaction.
(h) The cortical field may be considered in terms of differences in
permeability.
2. (a) Structural and ultrastructural differences between dorsal and
ventral cortex are still unknown.
(b) Difference in permeability to certain dyes ought to be
extended to physiological factors.
(c) The nature of the hypothetical interaction between cortex
and yolk should be investigated.
Acknowledgements
We express our warmest thanks to Profs. A. Dalcq and J. Mulnard
who read the manuscript and considerably improved the English.
References
Ancel, P. and Vintemberger, P. (1948). Bull, biol., Suppl. 31, 1.
Born, G. (1885). Arch. mikr. Anat. 24, 475-545.
Brächet, A. (1904). Arch. Biol. 21, 103.
Chambers, R. (1918). Proc.Soc. exp. biol., N.Y. 17, 41.
Curtis, A. S. G. (1960). J. Embryol. exp. Morph. 8, 163.
Curtis, A. S. G. (1962). J. Embryol. exp. Morph. 10, 231.
Dalcq, A. (1941). 'L'œuf et son dynamisme organisateur', 580 pp. Albin Michel,
Paris.
Dalcq, A. and Dollander, A. (1948). C. R. Soc. Biol., Paris 142, 1307.
Dalcq, A. and Pasteels, J. (1937). Arch. Biol. 48, 669.
Dalcq, A. and Pasteels, J. (1938). Bull. Acad. roy. Belg. 3, 261.
DoUander, A. (1950). Arch. Biol. 61, 1.
Dollander, A. (1952). C. R. Ass. Anat., 38ème Réun. Nancy, 430.
Dollander, A. (1952). C. R. Soc. Biol. Paris 146 1607