Definitions
from The American Heritage® Dictionary of the English Language, 5th Edition.
- noun A membranous sac that develops from the posterior part of the digestive tract in the embryos of mammals, birds, and reptiles. It is important in the formation of the umbilical cord and placenta in mammals.
from The Century Dictionary.
- noun A fetal appendage of most vertebrates, developing as a sac or diverticulum from the posterior portion of the intestinal cavity.
from the GNU version of the Collaborative International Dictionary of English.
- noun (Anat.) A membranous appendage of the embryos of mammals, birds, and reptiles, -- in mammals serving to connect the fetus with the parent; the urinary vesicle.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun anatomy A
sac , having a number of functions, that develops in thealimentary canal of theembryos ofmammals ,birds andreptiles .
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- noun the vascular fetal membrane that lies below the chorion and develops from the hindgut in many embryonic higher vertebrates (reptiles, birds and mammals)
Etymologies
from The American Heritage® Dictionary of the English Language, 4th Edition
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Examples
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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 J. Arthur Thomson 1897
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Inside, the amnion encloses the embryo in a protected, moist environment in which nourishment is supplied by the yolk sac, and metabolic waste is stored by the allantois.
Reptile 2008
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A very early condition of Man, with yelk-sac, allantois, and amnion (original).
Essays 2007
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The very young puppy, with attached ends of the yelk-sac and allantois, and invested in the amnion.
Essays 2007
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Aristotle's view, arguing that the female seed contrib - utes only nutrition and the allantois, while the male seed forms the other embryonic membranes (chorion, amnion) and bodily parts.
Dictionary of the History of Ideas D. M. BALME 1968
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It was known by the 1860's that various nutritive, respiratory, and excretory organs (yolk-sac, allantois) characteristic of embryos are lacking in all adults.
RECAPITULATION JANE OPPENHEIMER 1968
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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 R. A. Craig
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In the region of the posterior appendages, _pa_, the section passes through the hindgut, _hg_, and allantois, _al_.
Development of the Digestive Canal of the American Alligator C. M. [Illustrator] Reese
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The allantois, _al_, extends cephalad for some distance from the floor of the cloaca.
Development of the Digestive Canal of the American Alligator C. M. [Illustrator] Reese
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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
chained_bear commented on the word allantois
Reesetee, did you know this name? I didn't. (I thought it was just "membrane" or something... duh...)
It also sounds much prettier than it probably is.
August 28, 2008
reesetee commented on the word allantois
No, I didn't--or if I did, I've forgotten. But I think I have just the list for it.... :-)
August 28, 2008
jmjarmstrong commented on the word allantois
JM refused another allantois roll as he is really trying to give up.
January 9, 2010