. The elements of embryology . Embryology. Surface Views of the early Stages of the Segmentation IN A Fowl's Egg. {A and G after Coste.) A represents the earliest stage. The first furrow (5) has begun to make its appearance in the centre of the germinal disc, whose periphery is marked by the line a. In B, the first furrow is completed nearly across the disc, and a second similar furrow at right angles to the first has appeared. The disc thus becomes divided somewhat irregularly into quadrants by four (half) furrows. In a later stage ((7) the meridian furrows h have increased in number, from fo
. The elements of embryology . Embryology. Surface Views of the early Stages of the Segmentation IN A Fowl's Egg. {A and G after Coste.) A represents the earliest stage. The first furrow (5) has begun to make its appearance in the centre of the germinal disc, whose periphery is marked by the line a. In B, the first furrow is completed nearly across the disc, and a second similar furrow at right angles to the first has appeared. The disc thus becomes divided somewhat irregularly into quadrants by four (half) furrows. In a later stage ((7) the meridian furrows h have increased in number, from four, as in B, to nine, and cross furrows have also made their appearance. The disc is thus cut up into small central (c) and larger peripheral (d) segments. Several new cross furrows are seen just beginning, as ex. gr. close to the end of the line of reference d. appearance, running, across the germinal disc, though not for the whole breadth, and dividing it into two halves (Fig. G, A). This primary furrow is succeeded by a second at right angles to itself. The surface thus becomes divided into four segments or quadrants (Fig. 6,-B). 2—2. 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 Foster, M. (Michael), Sir, 1836-1907; Balfour, Francis M. (Francis Maitland), 1851-1882; Sedgwick, Adam, 1854-1913; Heape, Walter, 1855-1929. London ; New York : Macmillan
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Keywords: ., bookcentury1800, bookdecade1880, bookpubli, booksubjectembryology
