. The Century dictionary and cyclopedia; a work of universal reference in all departments of knowledge, with a new atlas of the world ... nal, the mesoblastic external; the process of inversionbeing comparable to that by which, in the case of theprimitive trace of the embrjo, a layer of epiblast is con-verted into the lining of the spinal canal. Only that foldof membrane which is next the body of the embryo co^jj- poses the anmion prop-er, the other or outerfold in contact with theenveloping primitivechorion (vitelline mem-brane or yolk-sac)eitherdisappearing or takingpart in the fonuation oft
. The Century dictionary and cyclopedia; a work of universal reference in all departments of knowledge, with a new atlas of the world ... nal, the mesoblastic external; the process of inversionbeing comparable to that by which, in the case of theprimitive trace of the embrjo, a layer of epiblast is con-verted into the lining of the spinal canal. Only that foldof membrane which is next the body of the embryo co^jj- poses the anmion prop-er, the other or outerfold in contact with theenveloping primitivechorion (vitelline mem-brane or yolk-sac)eitherdisappearing or takingpart in the fonuation ofthe permanent long as this outerfold is recognizable asa membrane, it bearsthe name of/alse am-nion. The shut sac ofthe anmion contains thelittuor amnii, a bland,albuminous, serous fluidin which the fetus is im-mersed. In parturition,rupture of the sac is fol-lowed by the biu-stingof the waters. Some-times a portion of thesac adheres to the headof the child, fitting likea skull-cap; such an in-fant is said, in the lan-guage of midwives, whocommonly regard as a goodomen, to be born witha caul. Those verte-. hA7n Vertebrate Embryo (chicle. 5th day ofincubation ;<,shon-ing .^m, the inclosingamnion: «, c, rudiments of anteriorand posterior limbs, or limb-buds: i,2, 3, first, second, and third cerebralvesicles; xa, vesicle of the third ven-triclc : A, eye : *, visceral arches andclefts; .4//, allantois, banking by itspedicle: Um, portion of umbilicalvesicle. amnion brates which possess nn amnion are termed Amnioimta;those which do not, Anaimiiv/iata: terms coinciilent re-spectively with Alltiiitoidea ami Atmllantoidea. 2. In cntom,, a membrane which surrounds thelarva of many insects, as the millepods {lulkia),for some time after they are hatched from tlieegg. It is regarded by some as the analogueof the amnion of a vertebrate. In many insects and in the hi-;her vertebrates, the em-bryo aciiuires a special protective envelope, the amnion,wluchis thrown
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