. The development of the chick : an introduction to embryology. Embryology; Chickens -- Embryos. ALIMENTARY TRACT AND ITS APPENDAGES 319 the adult cloaca. Even on the seventeenth day the large intes- tine appears to be still closed at its lower end, and the urodaeal membrane still persists as a plug of vacuolated cells. (Gasser.) Both plugs must, however, disappear soon after. It would thus appear that the urodseum only of the adult cloaca corresponds to the embryonic cloaca; the proctod2eum is certainly derived from an ectodermal pit, and it is probable that. Fig. 186.—Chick embryo of 11 days
. The development of the chick : an introduction to embryology. Embryology; Chickens -- Embryos. ALIMENTARY TRACT AND ITS APPENDAGES 319 the adult cloaca. Even on the seventeenth day the large intes- tine appears to be still closed at its lower end, and the urodaeal membrane still persists as a plug of vacuolated cells. (Gasser.) Both plugs must, however, disappear soon after. It would thus appear that the urodseum only of the adult cloaca corresponds to the embryonic cloaca; the proctod2eum is certainly derived from an ectodermal pit, and it is probable that. Fig. 186.—Chick embryo of 11 days, sagittal section through the region of the cloaca. Reconstructed from several sections. (After Minot.) Air., Ascending limb of the allantois. AH"., Descend- ing limb of the allantois. An., Anal invagination. , Urodeal membrane. Art., Umbilical artery. B. F., Bursa Fabricii. b. Duct of the bursa. Clo., Cloaca. Ec, Ectoderm. Ent., Entoderm of the rectum. Ly., Nodules of crowded cells, probably primordia of lym- phoid structures in the wall of the large intestine. W. D., Wolffian duct. the coprodaeum represents the enlarged lower extremity of the embryonic large intestine. The bursa Fabricii is an entodermal structure derived from the posterior portion of the embryonic cloaca. IV. The Development of the Liver and Pancreas The Liver. The anterior and posterior liver diverticula, de^ scribed in Chapter VI, constitute the rudiments from, which tne. 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
