1906.] ANATOMY OF THE OPHIDIA. 21 



connection with its perforation by the umbiHcal aperture. 

 It is as well developed as in the Ophidia generally, and lies, as in 

 other snakes, immediately above the middle line of the body. Its 

 posterior connection I did not see in either of the specimens. In 

 the region of the liver, this vein has two connections with the 

 hepatic portal system, and two only that were visible, which were 

 identical in both specimens and which therefore may be looked 

 upon as distinctive of the species. One branch from the vein 

 joined the main portal stem a little behind the point where it 

 reaches the liver. The other branch of the epigastric connected 

 with the hepatic portal system lies a long way anteriorly and 

 enters the liver- substance approximately in the middle line, a 

 very little way behind the anterior termination of the liver. I 

 saw no other veins passing from the epigastric to the liver. But 

 in an adult Eunectes nmirinits there were four or five veins 

 entering the liver between these two. It may be that the 

 existence of two only in the young Eunectes notceus is a mark of 

 immaturity. 



Afferent Renal Veins. — The caudal vein emerging from the 

 tail receives branches from the cloaca, of which I am not able to 

 give a particular account, as this region got damaged in displaying 

 the course of the main trunk of the vein. The vein runs close to 

 the large intestine on the left side, and receives in its course to the 

 left kidney a series of veins from the parietes to the left of the 

 dorsal median line (text-fig. 5, p. 17). I counted altogether twelve 

 of these before the vein enters the kidney, of which it is the afferent 

 renal. On the right side the afferent renal seems to have no direct 

 connection with the caudal vein, but the anastomoses between 

 veins in this region are so numerous that there is doubtless an 

 actual connection between them. Still there is no such direct- 

 continuity as obtains on the left side. It is also to be remarked 

 that the right renal afferent vein is a very distinctly smaller vein 

 than its fellow of the left side, and in correspondence with this the 

 affluents fi-om the parietes which join it are much less conspicuous 

 than those of the left side. 



The figure (text-fig. 5, p. 17) shows the series of veins from 

 the parietes which enter the left renal affei-ent vein. And an 

 inspection of this figure will render unnecessary a detRiled de- 

 scription of the veins in question. It may be remarked, however, 

 that there is a tendency for them to be connected together by a 

 longitudinal trunk which is not present throughout the whole 

 extent of the series, but gets to be more pronounced anteriorly. 

 These parietal veins moreover vary in importance, some being- 

 much more slender than others. The most prominent of the 

 whole series enters the afierent renal just before the latter enters 

 the left kidney. This vein is connected with a very conspicuous 

 longitudinal trunk (text-fig. 6, p. 23) which runs along the whole 

 length of the kidney, being stouter at the two ends of that organ 

 and more slender in the middle ; it is, however, nowhere deficient. 

 There is a general correspondence between the numbei'S of these 



