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allantois

NOUN
  1. the vascular fetal membrane that lies below the chorion and develops from the hindgut in many embryonic higher vertebrates (reptiles, birds and mammals)

How To Use allantois In A Sentence

  • Both the chorioallantoic placenta and CAM are derived from chorion and allantois PLoS ONE Alerts: New Articles
  • The lateral leaves of somatopleure then grow round on each side, and, meeting on the ventral aspect of the allantois, enclose the vitelline duct and vessels, together with a part of the extra-embryonic celom; the latter is ultimately obliterated. I. Embryology. 11. Development of the Fetal Membranes and Placenta
  • Thus in many mammals the mesodermal part of the allantois often appears long before the endodermal part, though this is phylogenetically older. Form and Function A Contribution to the History of Animal Morphology
  • It is an interesting point that this vascular hood, called the allantois, is represented in the Amphibians by an unimportant bladder growing out from the hind end of the food-canal. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told
  • It would he difficult for a mutationist to explain how a mutation should affect the development of the cloacal bladder to such an enormous degree, just when it was required for embryonic respiration, and cause the sides of the body to unite ventrally at the time of hatching, cutting off the allantois and the amnion. Hormones and Heredity
  • Thus in many mammals the mesodermal part of the allantois often appears long before the endodermal part, though this is phylogenetically older. Form and Function A Contribution to the History of Animal Morphology
  • Covering the external face of the amnion and lining the inner face of the chorion is a double membrane, _the allantois_. Common Diseases of Farm Animals
  • Among the important changes of the vertebrate organisation that marked the rise of the first Amniotes from salamandrine Amphibia during this period the following three are especially noteworthy: the entire disappearance of the water-breathing gills and the conversion of the gill-arches into other organs, the formation of the allantois or primitive urinary sac, and the development of the amnion. The Evolution of Man — Volume 2
  • The pedicle of the allantois, which connects the embryo with the placenta and conducts the strong umbilical vessels from the former to the latter, is covered by the amnion, and, with this amniotic sheath and the pedicle of the yelk-sac, forms what is called the umbilical cord (Figure 1.196 al). The Evolution of Man — Volume 1
  • The urachus is a remnant of allantoic origin, connecting the embryonal cloaca to the allantois during early intrauterine life.
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