CHANGES IN FETAL \'ESSELS OF THE LIVER 481 



ments in the dog are wholly comparable to those in the sheep and 

 that they occur with approximately equal rapidity. 



A similar condition was also found in a dog about four months 

 old. In this animal the one remnant of the umbilical vein was 

 a fine strand about 5 mm. long and 1 to 1.5 nun. thick which was 

 attached to and lay on the ventral wall of the portal vein at 

 its bifm'cation. The suspensory ligament too was somewhat 

 smaller than in the above animal. Moreover, on one of several 

 dogs only seven weeks old both the suspensory ligament and 

 the umbilical vein had completely disappeared save for a very 

 fine filament of peritoneum which extended from a point oppo- 

 site the tip of the ensiform cartilage to the left portal vein. 

 At the proximal or hepatic, end of this filament a small, short 

 remnant of the umbilical vein was still present. In the other 

 dog only a small filament 2.5 cm. long which was partly fibrous, 

 was still attached to the left portal, and the suspensory ligament 

 had completely disappeared save for a fine strand of peritoneum 

 which was suspended from the ventral abdominal wall near the 

 tip of the xiphoid process. However, that considerable vari- 

 ation exists in the time of the disappearance of the suspensory 

 ligament, at least, is shown by the fact that in two dogs about 

 one and one-half years old the suspensory ligament which was 

 still present, began at a point opposite the middle of the xiphoid 

 ])rocess. Yet the umbilical vein had wholly disappeared in 

 both these animals. The findings in two pu])8 three weeks old 

 and especially in two new-born dogs are in marked contrast to 

 those in the last two animals. In these four pups the suspensory 

 ligaments had completely disappeared except for a very small 

 falciform portion directly ^'entral to the vena cava. In both the 

 new-]3orn animals the umbilical veins ran directly from the left 

 ])ortal to the uml^ilicus and was completely isolated. Hence 

 it is evident that whenever this condition exists the formation 

 of a round ligament in the caudal boixler of the suspensory liga- 

 ment had never included the vein or had alreatly degenerated 

 before birth, the latter was isolated and hence could no more 

 fonn a ligament after becoming detached from the umbilicus 

 than the oiniihalomescnteric or hvjiogastric vessels can do so after 



