A system of obstetrics . this archenteronare subsequently added an anterior portion (stomadseum) and a posterior(proctodeum); both of these are lined by epiblast and pitted in fromthe exterior (Figs. 43 and 57). The archenteron soon shows a dhTerentation into three regions: thepart of it which lies originally within the head-fold is known as thefore-gut; from it the lungs, pharynx, gullet, stomach, and duodenumare derived. The posterior portion of the archenteron is short and lieswithin the tail-fold ; most of the rectum is formed from it, as also theallantois and its derivatives (urinary blad
A system of obstetrics . this archenteronare subsequently added an anterior portion (stomadseum) and a posterior(proctodeum); both of these are lined by epiblast and pitted in fromthe exterior (Figs. 43 and 57). The archenteron soon shows a dhTerentation into three regions: thepart of it which lies originally within the head-fold is known as thefore-gut; from it the lungs, pharynx, gullet, stomach, and duodenumare derived. The posterior portion of the archenteron is short and lieswithin the tail-fold ; most of the rectum is formed from it, as also theallantois and its derivatives (urinary bladder, etc.): it is named the DEVELOPMENT OF ORGANS AND SYSTEMS. 187 hind-gut. The median portion of the archenteron remains for a con-siderable period open on its ventral side, where its walls spread apartto form the umbilical vesicle (Fig. 124). It is known as the mid-gut ormesenteron, and is at first relatively short: as it closes-in it elongatesand forms the greater part of the small and large intestines. Fig. B.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectobstetrics, bookyear1
