Die Symmetrieverhältnisse der Eingeweide, der Habenulakerne und des Darmvenensystems bei dorsal-dorsal und ventral-ventral verwachsenen Parabioselarven des Bergmolches (Triturus alpestris)

Symmetry and Asymmetry in the Development of Inner Organs in Parabiotic Twins of Amphibians (Urodela)

“…The most prominent structure of the vitelline vein system is the vitelline vein itself (vena subintestinalis, Figs. 4h, 9a; von Kraft, 1971bKraft, , 1973Kraft, , 1976bKraft, , 1990Kraft, , 1991Kraft, , 1995a. The direction of the blood flow in this vessel, which is almost always pointing to the left-hand side of normal individua l embryos (normal situs, Fig.…”

“…3d,4f,g,6e,f). In the experimental group DD-N (von Kraft, 1995a), in spite of a dorsaldorsal fusion of the embryos, in many cases a dorso-ventral polarisation (von Kraft, 1991) of the parabiotic twins occurs: one can distinctly discern a``pairdorsal side' ' from a``pair-ventral side' ' , and accordingly a``left' ' and a``right' ' parabiont, analogous to the Ho-parabionts (Fig. 4d, Table 1).…”

“…217 & 224) may transiently assum e an asymm etric appearance during the embryonic development of am phibians. The most detailed studies of these organ asymm etries, concerning both m orphology and developm ental physiology, were performed using the newt Triturus alpestris (von Kraft, 1971a(von Kraft, , 1976a(von Kraft, ,b, 1986(von Kraft, , 1995avon W oellwarth, 1950;W ehrm aker, 1969).…”