348 



Veterinary Obstetrics 



rrimitiz'e grooz'e. 



Entoderm. 



Fig. 67. Transverse section of the embryonic area of a fourteen-and-a-half-day 

 ovum of sheep. ( Heisler, after Bonnet). 



Amnion. 



i'leu roperica r- 

 dial cavity. 



Fig. 68. Transverse section of a sixteen-and-a-half-day sheep-embryo. 

 (Heisler, after Bonnet), 

 day of gestation 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 ari.ses 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 



