368
G. V. LOPASHOV AND O. G. STROEVA
action between the intraocular pressure and the mesenchyme envelopes
of the eye opposing it, there occurs morphogenesis at the supracellular
level: formation of the ciliary body and corneal curvature, differentiation and growth of the sclera and cornea, general growth of the eye and
proportional growth of the retina and pigment epithelium. The formation of the eye cup by the retina stretching around the lens proceeds in
the same manner. A single factor acts here which can produce different
effects on different parts, depending on their initial structure and
geometrical position in the eye. Under the formative and correlating
action of this factor the form and structure of the definitive organ are
created. Accordingly, the elimination of the intraocular pressure affects
the form and size of both the individual rudiments and the organ as a
whole. No changes occur at the cytological level, with the exception of
marginal zones of the pigment epithelium in Mammals.
These phases are simultaneously realized in each individual rudiment
and in the organ as a whole, since the development of all parts is closely
interconnected. But if within the individual rudiments these phases are
clearly delimited in time they often overlap in the eye as a whole. For
example, the formation of the cup proceeds before the termination of the
second phase, while the dependence of the differentiation of the pigment
epithelium on stretching in Mammals extends into the third phase.
It is impossible to say thus far, how much all these main phases are
needed for the complete differentiation of each rudiment. However for
those rudiments the development of which has been studied more
completely, all are needed. From this viewpoint it is useful to analyse
the extent of our knowledge of different parts of the eye.
Eye vesicle and its derivatives. Separation of the eye rudiment (§11)
from which the vesicle is formed is the first stage for all its derivatives.
The second and third stages are well studied for the retina and pigment
epithelium (§111), while only the third stage is studied for the ciliary body.
Can the second phase of the development of the ciliary body be realized
during the contact between the marginal zone of the eye cup with the
lens (§IH)? The second and third phase have not been studied in the development of the iris.
Ectodermal derivatives. All three phases are described for the cornea
(§V), while the first and the second are described, in outline, for the
lens (§IV). What determines the form of the lens and the radii of curvature
of its anterior and posterior surfaces which differ widely in the representatives of different systematic and ecological groups? Is the period when
they come into being the third phase in the development of the lens?
Mesenchyme envelopes. In the formation of the sclera the third phase
of its development is well studied (§VI). However, the data on causal
relations in the morphogenesis of the sclera, and especially of the choroid
G. V. LOPASHOV AND O. G. STROEVA
action between the intraocular pressure and the mesenchyme envelopes
of the eye opposing it, there occurs morphogenesis at the supracellular
level: formation of the ciliary body and corneal curvature, differentiation and growth of the sclera and cornea, general growth of the eye and
proportional growth of the retina and pigment epithelium. The formation of the eye cup by the retina stretching around the lens proceeds in
the same manner. A single factor acts here which can produce different
effects on different parts, depending on their initial structure and
geometrical position in the eye. Under the formative and correlating
action of this factor the form and structure of the definitive organ are
created. Accordingly, the elimination of the intraocular pressure affects
the form and size of both the individual rudiments and the organ as a
whole. No changes occur at the cytological level, with the exception of
marginal zones of the pigment epithelium in Mammals.
These phases are simultaneously realized in each individual rudiment
and in the organ as a whole, since the development of all parts is closely
interconnected. But if within the individual rudiments these phases are
clearly delimited in time they often overlap in the eye as a whole. For
example, the formation of the cup proceeds before the termination of the
second phase, while the dependence of the differentiation of the pigment
epithelium on stretching in Mammals extends into the third phase.
It is impossible to say thus far, how much all these main phases are
needed for the complete differentiation of each rudiment. However for
those rudiments the development of which has been studied more
completely, all are needed. From this viewpoint it is useful to analyse
the extent of our knowledge of different parts of the eye.
Eye vesicle and its derivatives. Separation of the eye rudiment (§11)
from which the vesicle is formed is the first stage for all its derivatives.
The second and third stages are well studied for the retina and pigment
epithelium (§111), while only the third stage is studied for the ciliary body.
Can the second phase of the development of the ciliary body be realized
during the contact between the marginal zone of the eye cup with the
lens (§IH)? The second and third phase have not been studied in the development of the iris.
Ectodermal derivatives. All three phases are described for the cornea
(§V), while the first and the second are described, in outline, for the
lens (§IV). What determines the form of the lens and the radii of curvature
of its anterior and posterior surfaces which differ widely in the representatives of different systematic and ecological groups? Is the period when
they come into being the third phase in the development of the lens?
Mesenchyme envelopes. In the formation of the sclera the third phase
of its development is well studied (§VI). However, the data on causal
relations in the morphogenesis of the sclera, and especially of the choroid