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ARTHUR WILLIAM MEYER 



them might require modification as a result of a more compre- 

 hensive series of observations. There is no question, however, 

 that in all these animals the umbilical vein ultimately disappears 

 first near the umbilicus, i.e., centripetally and not centrifugally 

 as Robin and Herzog stated it does in man. It is also clear that 

 the reason that the round ligament in most of the domestic 

 animals usually seems to begin at the tip of the xiphoid is that 

 the vein has retracted and degenerated and is forced against the 

 ventral abdominal wall between the umbilicus and xiphoid by 



Fig. 3 Drawing of the unrolled bortler of an accessory free fold from the 

 suspensory ligament to the gall bladder of the dog. The large thick-walled 

 vein is shown at a point where one of its bi-anches joins, a, vein; b, fat. X42. 



the narrow regressing suspensory ligament in whose crescentic 

 border it comes to lie, although in doing so it manifestly must 

 take a more roundabout course than before. This is, no doubt, 

 due to the fact that after its initial retraction the vein which is 

 enclosed in the caudal border of the suspensory ligament is drawn 

 cranially as a result of pre- or post-natal changes. Moreover, 

 it is not at all unlikely that as a result of these factors the free 

 caudal border of the ligament also becomes markedly concave 



