38 VETERINARY OBSTETRICS. 



irregularly distributed, being very numerous, especially 

 about the horns, while at other situations they may be 

 absent. 



In the Bitch, the vascular connection has been 

 termed "zonular." The tufts are arranged in a ring or 

 circle around the external aspect of the chorion, 

 contacting a similar circle on the internal aspect of the 

 uterus. This zone or circle is from one and a half to 

 two inches broad. 



In animals which give birth to more than one foetus 

 at a time, each foetus may have a separate chorion and 

 umbilical cord complete, and in this case that portion 

 of the chorion which is in contact with another 

 chorion, and not in contact with the wall of the uterus, 

 has no vascular tufts. In other cases, there is one 

 common chorion, and from it each foetus is supplied 

 with an umbilical cord, through which it derives its 

 nourishment. 



Tlmbilical Cord. 



This forms the means of communication between 

 the parent and foetus. 



In the Mare, besides the tissue proper of the cord, 

 it consists of two arteries and one vein. The arteries 

 are given off by the internal iliacs of the foetus, pass 

 along the lateral aspect of the bladder, and leave 

 the abdomen (of the foetus) at the umbilical opening. 

 They then give off some small nutrient branches to 

 the structure of the cord, pass outward, and break up 

 into a great number of smaller vessels, which ramify 

 between the external surface of the allantoid membrane 



