Definition of allantois in English:

allantois

Syllabification: al·lan·to·is
Pronunciation: /əˈlantō-is
 
/

noun (plural allantoides /ˌalənˈtō-idēz/)

  • The fetal membrane lying below the chorion in many vertebrates, formed as an outgrowth of the embryo’s gut. In birds and reptiles it grows to surround the embryo; in eutherian mammals it forms part of the placenta.
    More example sentences
    • The urachus is a remnant of allantoic origin, connecting the embryonal cloaca to the allantois during early intrauterine life.
    • In the fetus, the urachus connects the bladder with the allantois.
    • Initially, the bladder is continuous with the allantois.

Derivatives

allantoic

Pronunciation: /ˌalənˈtō-ik/
adjective
More example sentences
  • We're talking about things like the amnion, the chorion, the allantoic sac, the placenta, the umbilical cord, if those words sound familiar to you.
  • Veterinarians are completing the study comparing allantoic and amniotic fluids and heart rates of fetuses in mares.
  • The embryo forms an allantoic placenta, as is true of at least some peramelids and koalas but not other marsupials.

allantoid

adjective
More example sentences
  • The spores are white, and are cylindrical to allantoid in shape.
  • HvAV - 3a virions vary from allantoid to bacilliform, and are not occluded in occlusion bodies.
  • When screening germ plasm for Karnal bunt resistance, allantoid secondary sporidia produced in solid media should be used as inoculum.

Origin

mid 17th century: modern Latin, based on Greek allantoeidēs 'sausage-shaped'.

More definitions of allantois

Definition of allantois in:

Get more from Oxford Dictionaries

Subscribe to remove adverts and access premium resources

Word of the day astrogation
Pronunciation: ˌastrə(ʊ)ˈgeɪʃ(ə)n
noun
(in science fiction) navigation in outer space