. Anatomischer Anzeiger. Anatomy, Comparative; Anatomy, Comparative. 213 deepens and spreads, finally nearly filling the cell, in which a com- paratively light margin is left. In Fig. 2 are shown three sketches of a cell, which measures 100 ^i in its long diameter, and occupies a similar position to cell c in Fig 1. The sketches were made at intervals of a few minutes. The chromatophore was originally round; in Fig. 2 a, it is elongated; in 2 b, it has divided, and faint pigment lines outline the spindle; in 2 c, the division is complete. Mean- time the cell has changed its shape, and it soon
. Anatomischer Anzeiger. Anatomy, Comparative; Anatomy, Comparative. 213 deepens and spreads, finally nearly filling the cell, in which a com- paratively light margin is left. In Fig. 2 are shown three sketches of a cell, which measures 100 ^i in its long diameter, and occupies a similar position to cell c in Fig 1. The sketches were made at intervals of a few minutes. The chromatophore was originally round; in Fig. 2 a, it is elongated; in 2 b, it has divided, and faint pigment lines outline the spindle; in 2 c, the division is complete. Mean- time the cell has changed its shape, and it soon divides. Appearance of blastopore lip. At the end of the de- lamination period, the cells of the randzone are for the most part 40 /< in diameter, while the neighboring yolk cells measure 80 The zone, however, at its periphery, continues to pass insensibly into the yolk. The first step, visible in surface views, in the formation of the dorsal, and indeed of the rest of the blastopore lip, consists in what I may speak of as the "lining up" of the ectoderm cells. Hitherto there has been absolutely no line between yolk and future ectoderm. Now we find a few of the marginal pale brown cells, at first only two or three (as in Fig. 3), drawn up so that their lower edges (edges towards yolk pole) form a continuous, though by no means even line. The yolk cells on the opposite side of the line. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Anatomische Gesellschaft. Jena : G. Fischer
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