. Bulletin of the British Museum (Natural History), Geology. . Fig. 108 Elea whiteleyi sp. nov., VH 10539, top Lower Cenomanian (orbignyi Zone) - basal Middle Cenomanian (costatus Zone), Saint-Germain-la-Campagne, descente sur Orbiquet, Eure, France; primary rostrozooid containing intramural rostrozooid in turn containing intramural demizooid, x 120. been studied with their microstructure sufficiently well- preserved to prove that the wall which lines the lumen is an exterior wall rather than an interior wall, the transverse folding and wrinkling of this wall (Fig. 119) strongly suggests that
. Bulletin of the British Museum (Natural History), Geology. . Fig. 108 Elea whiteleyi sp. nov., VH 10539, top Lower Cenomanian (orbignyi Zone) - basal Middle Cenomanian (costatus Zone), Saint-Germain-la-Campagne, descente sur Orbiquet, Eure, France; primary rostrozooid containing intramural rostrozooid in turn containing intramural demizooid, x 120. been studied with their microstructure sufficiently well- preserved to prove that the wall which lines the lumen is an exterior wall rather than an interior wall, the transverse folding and wrinkling of this wall (Fig. 119) strongly suggests that it is an exterior wall. Rare examples of colony bases viewed from the underside (Fig. 122) show that the lumen of each branch opens at the colony base and that the lumen wall is smoothly continuous with the basal lamina. As the basal lamina is an undoubted exterior wall, this observation is further evidence that the lumen walls are exterior. In 5. vieilbanci occasional transverse platforms partition the axial lumen and seem to have been formed by progressive constric- tion of the lumen. The presence of these platforms, which would have periodically sealed the entrance to the lumen at branch growth tips, may explain why fouling of the apparent exterior walls lining the lumen has not been observed (cf. exterior walls lining the tubes of cavariiform Reptomultelea colonies). The platforms also imply that branches could not have grown around another erect organism (cf. some species of Reptomultelea), but instead grew freely into space. The phylogenetic relationship is unclear between Semielea and species of Meliceritites on the one hand and of Reptomul- telea on the other. Assuming Semielea to be a relatively advanced genus, it could have derived from either of the two latter genera. Derivation from Meliceritites would necessitate Fig. 109 Elea whiteleyi sp. nov., VH 10538, holotype, top Lower Cenomanian (orbignyi Zone) - basal Middle Cenomanian (costatus Zone), Saint-Germain-la-Cam
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