. The development of the chick; an introduction to embryology . is linedwith entoderm and has a thick mesodermal floor in which numer-ous small l)lood-vessels are already present. A transverse section(Fig. 81) shows that the thick mesodermal wall is l)roa(lly fusedwith the somato])leure in the region of the neck. In otherwords, the allantois is develoi)ed within the ventral will also be seen 1)y comparing these figures that the amnion 144 THE D]:VELOPMENT OF THE CHICK arises from the lUM-k of the allantois both behind and also at tliesides, (cf. Iig. S2.) During the fourth day tli
. The development of the chick; an introduction to embryology . is linedwith entoderm and has a thick mesodermal floor in which numer-ous small l)lood-vessels are already present. A transverse section(Fig. 81) shows that the thick mesodermal wall is l)roa(lly fusedwith the somato])leure in the region of the neck. In otherwords, the allantois is develoi)ed within the ventral will also be seen 1)y comparing these figures that the amnion 144 THE D]:VELOPMENT OF THE CHICK arises from the lUM-k of the allantois both behind and also at tliesides, (cf. Iig. S2.) During the fourth day tlie distal portion of tl^e allantoispushes out into the portion of the extra-embryonic body-cavitybeneath the hind end of the embryo and rapidly expands to forma relatively large sac. But the neck of the allantois remainsembedded in the ventral mesentery and does not expand; theterminal portion of the intestine has in the meantime formed Am- Am coy. Ect. -^ /VC-/J arS^^ ^ss^kyo--^ ^sSS .^r^SSru ,r=»9.„. *rcr9^7vt^ ^*.JS535.^,»» oS«._ - ^^ 1 •>^-- ,^.
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Keywords: ., bookcentury1900, bookdecade1900, bookiddevelopm, booksubjectbirds
