Measurements of the ultrastructural characteristics of SJs (A–D), graphically demonstrated by box-and-whiskers plots. Individual measurements are represented with dots and the numbers below the box-plots represent the number of measurements. The following stages were included in the analysis: mid-stage embryos S13 (S13), late-stage embryos S16 (S16), early-stage marsupial mancae (EMM), mid-stage marsupial mancae (MMM), late-stage marsupial mancae (LMM), postmarsupial mancae 3 days (PMM3), and 14 days (PMM14) after release from marsupium and adults. The letters above box-plots indicate significant differences between developmental stages (Mann-Whitney, p < 0.05). Measurements of the length of a continuous array of septa (A) in embryonic stages were pooled for statistical tests. Abbreviations: SJ: septate junction.