E X P E R I M E N T S ON EMBRYONIC AORTIC ARCHES 349
teric arteries. From this vast quantity of material only three examples
are discussed in the following paragraphs, and only the coeliac artery
will be discussed in detail.
1. The Shifting of the Root of the Coeliac Artery
The peculiar position of the root of the coeliac artery in chick
embryos was investigated by Bremer (1924, 1926), in an attempt to
explain the mechanism of its shift from the original median position on
the 3rd day of incubation. He came to the conclusion that the asymmetrical growth of sympathetic nerve fibres of the plexus coeliacus
causes the shifting of the coeliac root to the right dorsolateral wall of the
descending aorta. In our material (Rychter and Lemez, 1962a), in
which 1222 experimental embryos were examined, a shift of the coeliac
root from the definitive position, or from the developmental point of
view a diminished shift from the original position, or even a shift to the
left side of the aorta, was observed in 222 embryos. It is surprising that
Stephan does not mention this shift as occurring in his material, though
he had at his disposal some combinations which must have produced it.
FIG. 17. Effects of various patterns of substitute arcus aortae on the shift of the
coeliac root.
M2
A.M. 2
teric arteries. From this vast quantity of material only three examples
are discussed in the following paragraphs, and only the coeliac artery
will be discussed in detail.
1. The Shifting of the Root of the Coeliac Artery
The peculiar position of the root of the coeliac artery in chick
embryos was investigated by Bremer (1924, 1926), in an attempt to
explain the mechanism of its shift from the original median position on
the 3rd day of incubation. He came to the conclusion that the asymmetrical growth of sympathetic nerve fibres of the plexus coeliacus
causes the shifting of the coeliac root to the right dorsolateral wall of the
descending aorta. In our material (Rychter and Lemez, 1962a), in
which 1222 experimental embryos were examined, a shift of the coeliac
root from the definitive position, or from the developmental point of
view a diminished shift from the original position, or even a shift to the
left side of the aorta, was observed in 222 embryos. It is surprising that
Stephan does not mention this shift as occurring in his material, though
he had at his disposal some combinations which must have produced it.
FIG. 17. Effects of various patterns of substitute arcus aortae on the shift of the
coeliac root.
M2
A.M. 2