AExcFIG 5: Excretory canal with enlarged lumen in a day 7 adult.

A. Diagram of the C. elegans body showing the two possible positions of panels B-E with grey boxes. These panels include the proximal and distal gonad arms adjacent to the intestine.
B&C. Transverse sections from a young adult (B) and a day 7 adult (C). The bilateral excretory canals are colored in pink. Excretory canals in this day 7 adult slightly irregular apical borders and are asymmetric bilaterally.
D. Higher magnification view of an excretory canal from a different young adult animal showing the arrangement of the excretory canal (pink outline) among the hypodermis (Hyp, yellow outline) and seam cell (brown outline).
C&E.The hypodermis and seam cells in this region have pulled away from the cuticle on the left and right sides of the body, leaving large open spaces beneath the cuticle, and the remaining hypodermis and seam have thinned almost to vanishing, becoming more electron dense as they surround the excretory canals. The reproductive organs (gonad) have also shrunken, leaving behind a vast liquid space beneath the hypodermal layer, filled with large, electron-dense yolk/lipid particles.
E. Enlarged view of one excretory canal from (C).
Scale bars, 5 microns. (Image source: B: N506 [D. Hall] N290, C: N822 [D. Hall] 4685, D: N501 [D. Hall] BU4 008408.)

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