34'^ 



I 'etei'iiiai'y Obstetrics 



amnion fold. 





Visccial h-iy^r 



of 7nesjdeflti. En1od.-rm. 



Fig. 67. Transverse section of the embryonic area of a fonrteen-ancl-a-half-day 

 ovum of sheep. ( Heisler, after Bonnet ). 



Amnion. . 



rUuropeyiC'i 

 dial cavity 



Fii',. 68. Transverse section of a sixteen-and-a-half-day sheep-embryo. 

 (Heisler, after Bonnet). 



dav of prestation in the embryo of the sheep and i.s soon complete. 

 The date of its appearance in other domestic animals is approxi- 

 mately the same. 



The amnion arises from the extra-fetal portion of the somato- 

 pleure, which folds upward around the margin of the embryonic 

 area beneath the zona pellucida, or prochorion. It forms a double 



