BLASTOGENESIS AND MORPHOGENESIS
PAUL BRIEN
1
Torley-Rousseau
Institute of Zoology, Free University of Brussels, Brussels, Belgium
I. Introduction
151
II. Blastogenic Localization—Physiological Isolation
152
III. Origin of Blastogenic Cells
163
A. Morphallaxis
171
B. Histoblasts and Neoblasts
173
IV. Blastogenesis and Somatic Continuity
177
V. Blastogenesis and Renewal of Germ Cells
178
VI. The Organization of the Bud
182
VII. Correlative Competition—Total Potentiality and Restricted Potentiality
187
VIII. Double Ontogenesis or Multiple Ontogenesis
192
IX. Blastogenesis and Epigenetic Evolution
199
X. Conclusions
201
General References
201
Special References
202
I. Introduction
Sexual reproduction is basic and general among the metazoans. A
sexual reproduction may be added secondarily and sporadically in certain
phyla and zoological classes: sponges, coelenterates, annelids, bryozoans,
some echinoderms, pterobranchs, and tunicates.
Thus asexual reproduction has neither the universality nor the striking
unity of sexual reproduction. Its manifestations are as varied as the
organization of the animals which exhibit it.
There has been no important comprehensive work in this area since
the publication, in 1910, of "Ungeschlechtliche Fortpflanzung und Regeneration" (Korschelt and Heider, 1910). However, our knowledge has
increased considerably and become more specific, making a review and
synthesis of this material of value.
The reproductive unit in asexual reproduction is not a cell, like the
ovum of sexual reproduction, but is a multicellular fragment, or bud,
often heterogeneous and complex, derived from one parent. Its structure
is thus a function of the anatomy of the budding animal, and conse1
Translated from the French by Florence M. Foote, Department of Physiology,
Southern Illinois University, Carbondale, Illinois, U.SA.
151
PAUL BRIEN
1
Torley-Rousseau
Institute of Zoology, Free University of Brussels, Brussels, Belgium
I. Introduction
151
II. Blastogenic Localization—Physiological Isolation
152
III. Origin of Blastogenic Cells
163
A. Morphallaxis
171
B. Histoblasts and Neoblasts
173
IV. Blastogenesis and Somatic Continuity
177
V. Blastogenesis and Renewal of Germ Cells
178
VI. The Organization of the Bud
182
VII. Correlative Competition—Total Potentiality and Restricted Potentiality
187
VIII. Double Ontogenesis or Multiple Ontogenesis
192
IX. Blastogenesis and Epigenetic Evolution
199
X. Conclusions
201
General References
201
Special References
202
I. Introduction
Sexual reproduction is basic and general among the metazoans. A
sexual reproduction may be added secondarily and sporadically in certain
phyla and zoological classes: sponges, coelenterates, annelids, bryozoans,
some echinoderms, pterobranchs, and tunicates.
Thus asexual reproduction has neither the universality nor the striking
unity of sexual reproduction. Its manifestations are as varied as the
organization of the animals which exhibit it.
There has been no important comprehensive work in this area since
the publication, in 1910, of "Ungeschlechtliche Fortpflanzung und Regeneration" (Korschelt and Heider, 1910). However, our knowledge has
increased considerably and become more specific, making a review and
synthesis of this material of value.
The reproductive unit in asexual reproduction is not a cell, like the
ovum of sexual reproduction, but is a multicellular fragment, or bud,
often heterogeneous and complex, derived from one parent. Its structure
is thus a function of the anatomy of the budding animal, and conse1
Translated from the French by Florence M. Foote, Department of Physiology,
Southern Illinois University, Carbondale, Illinois, U.SA.
151