PHYSIOLOGY. 



35 



abdomen of the foetus at the umbilical opening, and 

 then passes backwards to join the anterior extremity of 

 the bladder, with the cavity of which the space between 

 the two layers of the allantois is in communication. It 

 is believed that the allantoid sac or cavity acts the 



Fig. i6. 



FcETAL Membranes of the Cow at Mid-term. 



A Uterus opened on its left side; B, B, Cotyledons of the Uterus; C, C, 

 ' Placentulse; D, D, Allantois; E, Vesicle of the Urachus; F, Amnion; 

 G, Umbilical Cord. 



part of a urinary reservoir during foetal life. The 

 constricted portion, which passes in at the umbilical 

 opening, has been called the "urachus." 



