480 ARTHTTK WILLIAM MEYER 



both the uinbihcal vein and the suspensory hgament which 

 would undoubtedly have been complete a few weeks later. Con- 

 sequently then, since the only remnant of the suspensory ligp - 

 ment in young sheep is a very small triangular fold and since 

 even this small remnant disappears practically entirely in older 

 animals it is evident that neither it nor the round ligament can 

 be said to exist in adult sheep for both disappear completely 

 during the first months of life. Evidently then the umbilical 

 vein never becomes ligamentous although fibrous transformation 

 may begin, but retracts and degenerates completely and the 

 suspensory ligament becomes fenestrated and undergoes practi- 

 cally total destruction. It is apparent and interesting, however, 

 that by far the greater portion of the suspensory ligament dis- 

 appears very rapidly and that a very small triangular cranial 

 portion may persist much longer or even permanently. 



What is true of the sheep, also holds for the dog for in no case 

 could a trace of either of these ligaments be found in mature 

 or old animals. Moreover, in a dog approximately a year old 

 there was not even an indication of the above-described teat- 

 like remnant of the umbilical vein attached to the left portal 

 as found in the sheep, and the suspensory ligament had aheady 

 been reduced to a very small triangular structure only about 

 1 cm. broad which again represented only the most cranio- 

 dorsal portion of the fetal structure. 



Likewise in dogs approximately two months old there was 

 only a vestige of the umbilical vein in the form of a short tag 

 and only a small triangular remnant of the suspensory ligament. 

 The latter measured 1.3 cm. along the diaphragmatic surface, 

 1.1 cm. on the hepatic and 9 cm. along its free caudal border. 

 Hence the original ligament can be said to have degenerated 

 almost completely. There was no round ligament whatever 

 and the umbilical vein had retracted and degenerated so com- 

 pletely that nothing remained of it save a small teat or process 

 3.5 mm. long and 1.5 mm. thick which projected from the wall 

 of the eft portal vein exactly in the position in which the similar 

 remnant had been found in the lamb. Hence it is evident that 

 the processes of obliteration of the round and suspensory liga- 



