. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. REDOX PATTERNS AND EXOGASTRULATION 69 than, the adjoining entoderm. The ectodermal polar gradient decreases basipetally and the cell-wall gradient remains as in normal development. Figure 2, D represents an exogastrula two days in water after one day in LiCl M/40. In the thicker distal entoderm intracellular oxidation decreases from the entodermal tip and the cell-wall gradient from the outer surface inward. In the proximal entodermal segment a polar gradient is present with decrease toward the ectoderm, but the cell-wall ha
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. REDOX PATTERNS AND EXOGASTRULATION 69 than, the adjoining entoderm. The ectodermal polar gradient decreases basipetally and the cell-wall gradient remains as in normal development. Figure 2, D represents an exogastrula two days in water after one day in LiCl M/40. In the thicker distal entoderm intracellular oxidation decreases from the entodermal tip and the cell-wall gradient from the outer surface inward. In the proximal entodermal segment a polar gradient is present with decrease toward the ectoderm, but the cell-wall has become so thin that presence of a cell-wall gradient is uncertain. In the ectoderm the polar and cell-wall gradients remain as in normal development. The exogastrulae of Figures 2, E and 2, F were two days in water after 25 hours in LiCl M/50. Th entodermal polar gradient decreased from the tip, the cell-wall. FIGURE 2. Oxidation patterns of Strongylocentrotus piirf>nratns: A, normal blastula; B, C, pre-exogastrulae; D-H, LiCl exogastrulae, some of mesenchyme cells becoming pigmented; data concerning experimental conditions in text. gradient from the external surface inward. In the case of Figure 2, E the ectoderm retained a slight polar gradient but no cell-wall gradient was distinguishable; in the exogastrula of Figure 2, F no ectodermal gradient was visible. The exogastrula of Figure 2, G, with the same treatment as E and F, was more inhibited than those, but with the same entodermal pattern and without distinguish- able gradient pattern in the ectoderm. Figure 2, H from the same lot of eggs, with the same treatment and in the same container as E-G, is an example of the regional differences in inhibition which may occur in the same lot. The entoderm is more, the ectoderm less inhibited than in most animals of the lot, but the entodermal oxi-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - colo
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