. The anatomical record. Anatomy; Anatomy. DEVELOPMENT OF MAMMALIAN CHORDA DORSALIS 249 which region the caudal end of the chordal canal is continuous with the ectoderm with total disappearance of the basal limiting membrane. The active mitosis of the ectoderm and deeper cells indicate a region of growth activity. Ventrally the mesodern is in continuity with the cells of the primitive node. The ento- derm passes uninterruptedly ventral to this area. In no por-. Kig. 10 A to F. Drawings o' representative cross sections of iuit)ryonic shield of the guinea pig, removed 14 days and 11 hours after
. The anatomical record. Anatomy; Anatomy. DEVELOPMENT OF MAMMALIAN CHORDA DORSALIS 249 which region the caudal end of the chordal canal is continuous with the ectoderm with total disappearance of the basal limiting membrane. The active mitosis of the ectoderm and deeper cells indicate a region of growth activity. Ventrally the mesodern is in continuity with the cells of the primitive node. The ento- derm passes uninterruptedly ventral to this area. In no por-. Kig. 10 A to F. Drawings o' representative cross sections of iuit)ryonic shield of the guinea pig, removed 14 days and 11 hours after insemination. The series embraces 188 sections shavingT^ thickness, and shows relations of the chor- dal plate. X 200. A, 30th section, with flattened chordal plate with entoderm extending beneath; B. 44th .section, with flattened chordal plate with entoderm extending beneath: C, 57th section, chordal plate incorporated in entoderm; D, 86th section, wide arched chordal plate incorporated in entoderm; E, 107th section distinctly arched chordal plate with entoderm extending beneath; F, 119th section, primitive node region. tion of this series, from region of the primiti\e node to cephahc end of head process was there observed a closed chordal canal, though in several regions the entoderm extends beneath the chordal plate, which results from dehiscence of the ventral wall of the chordal canal. In the regions in which the entoderm presents a cleft under the chordal plate, the edges of the cleft entoderm extend slightly under the borders of the chordal plate. THE .ANATOMICAL RECORD. VOL. 14, SO. 4. 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 Bardeen, Charles Russell, 1871-1935, ed; Boyden, Edward A. (Edward Allen), 1886-1976; Bremer, John Lewis, 1874- ed; Hardesty, Irving, b. 1866, ed; American Association of
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectanatomy, bookyear1906
