Fig. 5. The visceral musculature of the hindgut consists of syncytia throughout development. (A) First signs of GFP expression within the circular musculature of the hindgut (arrowheads) become visible in stage 15 embryos. (B) In some cases, labelling that overlapped visceral musculature of the hindgut (arrowhead) and larval somatic muscles (arrow) was detected. In the dissected hindgut of a third-instar larva (C), the reticulated structure of the individual muscles covering only one half of the gut tube becomes distinct. In adult flies (D), the circular muscles of the hindgut have lost their meshed structure and surround the gut tube as small bands, either entirely (arrowhead) or over about half its circumference (arrows).
