228 THE SALAMANDER 



a dorsal out-growth of the right lobe of the liver, the 'post-cavaF 

 lobe (Hohlvene Fortsatz, Hochstetter), which grows right down 

 to the point where the post-cardinals are constituted and invests the 

 vein very closely. 



The post-caval becomes visible again on the ventral surface of the 

 liver, just to the right of the gall-bladder, and it may be traced as a 

 dark line passing obliquely across the liver to emerge free once more 

 at the left edge of the pericardium, and, after a free course of about 

 6 mm., it enters the sinus venosus as already described. At the 

 junction between the post-caval vein and the sinus venosus a pair of 

 small veins enter, either together or separately. These have been 

 called by Hyrtl the 'Venae abdominales anteriores', and Joseph for 

 the sake of convenience adopts the same name. They are, however, 

 the mesial branches of the anterior epigastric veins. They arise on 

 either side by the bifurcation of the anterior epigastric veins into 

 mesial and lateral factors (see under factors of subclavian vein, p. 2 30) 

 at about the level of the posterior border of the coracoid. They pass 

 mesially, dorsal to the rectus abdominis muscle, to unite and enter 

 the sinus as described, or they may enter separately. The right 

 anterior epigastric vein is necessarily longer than the left, and re- 

 ceives a factor in the middle line dorsal to the sternal plate. This 

 small vein arises in the skin ventral to the sternum and passes either 

 posterior to, or through the cartilage to reach the dorsal side. It would 

 therefore seem best to call it simply the sternal vein. 



If now the liver tissue be carefully teased away from that portion 

 of the post-caval which passes through it, which is best done with 

 blunt needles or seekers, numerous hepatic veins will be found enter- 

 ing it from the liver. They enter from both sides, but, on the left, 

 there is usually one larger than the rest which is referred to as the 

 hepatic vein (v.h.s.). Very occasionally this larger vein may enter on 

 the right side. 



We may now consider the cases where the post-caval vein is 

 apparently wanting. There have been two such recorded, one by 

 Hochstetter (1888), and the other by Joseph ( 1 902), while Romeiser 

 (1905) summarizes these two cases and describes a similar occur- 

 rence in Necturus. Both the cases mentioned are essentially similar 

 except that in one it is the right, and in the other the left, post- 

 cardinal that hypertrophies to carry the additional blood. An ex- 

 amination of the liver in these cases revealed a pair of exceptionally 

 large right and left veins, more or less symmetrical, which fused near 

 the anterior end of the liver, and then emerged from it as a single 

 vessel to enter the sinus venosus in a precisely similar manner to the 



