Superficial Veins in the Pig. 445 



veine ombilicale, se trouvent en communication, a leur origine, avec 

 les veines epigastriques et les veines tegumenteuses de I'abdomen." 



Burow describes a vein formed from the union of branches from 

 the right and left epigastric. This vein passes up towards the liver 

 and enters the upper part of the umbilical vein. Joris maintains 

 that this vein is the same one as that described by Sappey, with 

 the difference that in the one case the vein enters the liver, and in 

 the other enters the unobliterated portion of the umbilical vein just 

 before it reaches the liver. He says, moreover, that the right as 

 well as the left umbilical vein may persist in the adult as a com- 

 munication between the liver and the right epigastric vein. His 

 work was done by injecting the portal vein after ligature of the 

 vena cava above and below" the liver. These injections were made 

 on foetuses two months old and older, and on a few infants. 



His has made a classification of these veins as follows: 



"(1) W parumbilicales (Sappeyi) welche von der Nabelgegend 

 aus zur Leber emporsteigen und in deren Substanz sich einsenken. . 



^'(2) V supra umbilicalis (Baumgarten's Burowsche Vene) welche 

 in das obere, offen gebliebene Ende der V. umbilicalis einmiindet. 



''(3) W umbilicovesicales. (Braunes' Burowsche Venen.) 



"(4.) W umbilicoepigastricae, welche beiderseits in die W epi- 

 gastricae inferiores profundae einmiinden." 



Summing up these observations it seems evident that ordinarily 

 there are some small venules running from the region of the dia- 

 phragm to the umbilicus, and that these connect the portal system 

 with small branches of the deep epigastrics. 



In pigs about three centimeters, in which all the vessels of the 

 membrana reuniens appear to have atrophied, sections show that 

 small vessels pass from the liver in the median line to the umbilical 

 vein, and that there are also some twigs connecting the umbilical 

 vein with the plexus in the region of the epigastric veins. However, 

 from a study of the vessels of the membrana reuniens in younger 

 embryos it is evident that the probability of variation is great which 

 naturally complicates studies of this kind very much. 



The smallest injected embryo considered here is one about 6 

 mm. (Fig. 1). It may be noted that this specimen is twisted upon 



