The American journal of anatomy . v f r h it 71-i ij— qranMi • *• mmand Fig. 12. A. punctatum, nearly median sagittal section of oropharyngealregion after the coalescence of the walls of the primitive mouth cavity. Theyolk-laden entoderm is surrounded by the ingrowing dental ridges. Ironhematoxylin, fuchsin. 4. Disappearance of Mouth Plate Ectoderm. In Amblystoma no stomodaeum is formed. Instead, the ectodermover the mouth plate area disappears, leaving the solid entodermexposed on the free surface. Later the mouth cavity appears as acleft in this entoderm. The well known arrangement of the ce
The American journal of anatomy . v f r h it 71-i ij— qranMi • *• mmand Fig. 12. A. punctatum, nearly median sagittal section of oropharyngealregion after the coalescence of the walls of the primitive mouth cavity. Theyolk-laden entoderm is surrounded by the ingrowing dental ridges. Ironhematoxylin, fuchsin. 4. Disappearance of Mouth Plate Ectoderm. In Amblystoma no stomodaeum is formed. Instead, the ectodermover the mouth plate area disappears, leaving the solid entodermexposed on the free surface. Later the mouth cavity appears as acleft in this entoderm. The well known arrangement of the cells of the ectoderm in twolayers is clearly marked in the mouth plate area of Amblystoma inthe neural plate stage. As the neural tube rolls up the ectoderm The Limit Between Ectoderm and Entoderm. 55 becomes somewhat thinner, but not as thin as that covering theventral surface of the yolk mass. Following this the inner cells ofectoderm disappear from the month plate. In either transverse orsagittal sections the entoderm is
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1910
