. Bulletin of the British Museum (Natural History), Geology. . Text-fig. 7. The cage at the base of the oospore in longitudinal section. A, C. Chara escheri. Oligo-Miocene. B. Chara hispida. Recent. All x c. 75. ( See Addendum, p. 216.) a few of the sections as a thin contracted brown line (PL 19, fig. 21). The spiral ridges on the membrane, marking the position of the lateral walls of the enveloping cells, are clearly shown (PL 19, fig. 24). The lateral walls, or flanges, are decorated with irregular granules which are coarser than those on the inner and outer membranes
. Bulletin of the British Museum (Natural History), Geology. . Text-fig. 7. The cage at the base of the oospore in longitudinal section. A, C. Chara escheri. Oligo-Miocene. B. Chara hispida. Recent. All x c. 75. ( See Addendum, p. 216.) a few of the sections as a thin contracted brown line (PL 19, fig. 21). The spiral ridges on the membrane, marking the position of the lateral walls of the enveloping cells, are clearly shown (PL 19, fig. 24). The lateral walls, or flanges, are decorated with irregular granules which are coarser than those on the inner and outer membranes (PL 19, fig. 27). Remains of the organic contents of the oospore are not preserved. It will be clear from a comparison with Text-fig. i b that there is a striking agree- ment between the structure of C. escheri and Recent Chara. The presence of a cage is especially interesting. The cages of the two species are compared in Text-fig. 7 (see also Text-fig. i B and PL 19, fig. 23). The statement by Groves & Bullock-Webster (1920: 58) that the cage at the base of the oospore encloses the stalk-cell appears to be inexact; for the ' transverse growth' to which they refer no doubt represents the thickened wall between the turning cell and the node-cell, or between the node-cell and the stalk-cell. Presumably it is the wall between the turning cell and node-cell, but there appears to be no statement on this in the literature (cf. de Bary, 1875: 300). The layering of the lime-shell is discussed on p. 201 above. The oospore membrane agrees in all respects with the equivalent membrane of existing charophytes. The inner and outer layers correspond to the inner and outer coloured membranes (Text-fig. 6) of Groves & Bullock-Webster (1920: 56). PL 19, fig. 24 of C. escheri may be compared with the decorated outer membrane of C. vulgaris in PL 19, fig. 20, and with the figures in Groves & Bullock-Webster. And the decorated inner membrane of C. escheri may be compared with the corres
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