. The development of the chick : an introduction to embryology. Embryology; Chickens -- Embryos. 188 THE DEVELOPMENT OF THE CHICK Figs. 109 and 110, until complete union of the two takes place (Fig. Ill) and there is established a complete dermo- myotomic plate in each somite, which therefore includes two layers: the external cutis-plate or dermatome, and the internal muscle-plate or myotome. With the elevation of the axis of the body, the dermo-myotome gradually assumes a nearly vertical Fig. no.—Transverse section through the seventeenth somite of a 29 s embryo. (Same embryo as Fi
. The development of the chick : an introduction to embryology. Embryology; Chickens -- Embryos. 188 THE DEVELOPMENT OF THE CHICK Figs. 109 and 110, until complete union of the two takes place (Fig. Ill) and there is established a complete dermo- myotomic plate in each somite, which therefore includes two layers: the external cutis-plate or dermatome, and the internal muscle-plate or myotome. With the elevation of the axis of the body, the dermo-myotome gradually assumes a nearly vertical Fig. no.—Transverse section through the seventeenth somite of a 29 s embryo. (Same embryo as Fig. 107.) am. Cav., Amniotic cavity. E. E. B. C, Extra-embryonic body-cavity. Gn., GangHon. mes'n. V., Mesonephric vesicle. , Sero-amniotic con- nection. Other abbreviations as before. Other details concerning the early history of the sclerotome are given in Chapter XIII, and it remains to add here only a short description of certain changes in the cells of the myotome (myo- blasts). In longitudinal sections the cells of the myotome are seen to become spindle-shaped soon after the folding towards the dermatome begins. The nuclei of the myoblasts are large and stain less deeply than those of adjoining tissues. They become elliptical in correspondence with the form of the cell- bodies. Each myoblast soon stretches from anterior to pos- terior faces of the somite, and this represents the first stage in the differentiation of the voluntary muscles. In later stages the myotomes send outgrowths into the limb- buds and ventral body-wall for the formation of the voluntary. 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 Lillie, Frank Rattray, 1870-1947. New York : Henry Holt
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Keywords: ., bookauthorlilliefrankrat, bookcentury1900, booksubjectembryology
