The development of the intra-intestinal artery in the Australian lungfish, Neoceratodus forsteri.

The development of the intra-intestinal artery in the Australian lungfish, Neoceratodus forsteri was studied by dye injection. The right arterior wall of the midgut changes to become the valvular wall of the original part of the spiral valve owing to the shift of the foregut towards the posterior and the left ventral to the midgut. The anlage of the intra-intestinal artery appears in the blood vascular network on the valvular wall of the original part of the spiral valve; this network receives arterial blood from the primitive coeliacomesenteric artery. The intra-intestinal artery is formed in such a manner that this anlage extends posteriorly in the blood vascular networks in the successive spiral valves.