Fig. 3. Displacement of H. vulgaris endoderm in heterografts. (A) 1-day-old heterograft with the H. vulgaris half placed distally and the H. oligactis half proximally. Inset, grafting site at higher magnification. (B) Longitudinal section through a heterograft similar to that shown in A. (C) Schematic representation of the section shown in B. Vul, tissues of H. vulgaris; Oli, tissues of H. oligactis. Note the clump of H. vulgaris endodermal tissue hanging into the gastric cavity. (D,E) H. vulgaris/H. oligactis heterografts 2 and 24 h after grafting, respectively. H. oligactis endoderm is labelled with fluorescent latex beads. (F) Brightfield view of the animal shown in E. Arrowheads indicate heterologous contact in the ectoderm.