506 MR. F. E. BEDDARD ON THE VASCULAR AND [May 1, 



That this vein originates from the afferent renal has been shown 

 by Hochstetter and myself in other Snakes*. The afferent 

 renal runs along the margin of the kidney and only dies away at 

 the veiy end anteiiorly. It is distinctly not continued forwards 

 as in the Pythonidee, or if so by the minvitest of twigs. In the 

 case of the right kidney, the renal afferent receives affluents from 

 the dorsal parietes along its course upon the kidney. The 

 existence of affluents occupying this position seems in the present 

 state of our knowledge to be a distinctive feature of the Colubrine 

 Snakes as opposed to the Boidse f. 



These affluents are two in number. The first is near to the 

 posterior end of the kidney, and is formed by the junction of two 

 intercostal veins. The second is at the end of the first third of the 

 kidney, and seems to arise from only one intercostal space. These 

 veins join the main trunk of the afferent renal; they do not plunge 

 independently into the kidney- substance, as they apparently do in 

 Erythrolcmiprtis. I could find no corresponding veins upon the 

 opposite side of the dorsal middle line supplying the left kidney. 

 The efferent renals do not retain their independence until they 

 are free of the region occupied by the kidneys. The two vessels 

 join at the anterior end of the left kidney, which is situated, as 

 in other Snakes, behind the larger right kidney. The anterior 

 part of the conjoined renal efferents, which is of course the vena 

 cava inferior, received twigs from the right kidney. It is to be 

 noted that in both cases the branches flowing from the kidneys 

 into the venae renales efferentes have a free course of some 

 millimetres after emerging from the kidney-tissue. 



Hepatic Portal System. — The portal vein receives very few 

 affluents from the parietes before it reaches the liver. Directly 

 after reaching the liver the portal trunk shows a spiral twisting, 

 such as is figured by Hochstetter % in the case of the portal vein 

 of Lacerta, just before entering the liver. As in other Snakes, 

 the portal runs to the extreme anterior end of the liver. The 

 affluents of the vein are, as usual, dorsal and ventral. 

 The dorsal affluents are mainly in the region of the liver. In fact 

 I could find only one dorsal parietal vein before the liver is 

 reached. This vein, which springs from three intercostal spaces, 

 joins the portal in the region of the gall-bladder, and corresponds 

 in position with the first mesenteric artery. It is apparently 

 general in Snakes for a vein to exist in this region. In the course 

 of the liver, the portal receives seven or eight twigs from the dorsal 

 parietes, which all arise from the left side of the ver-tebral column. 

 These are roughly at equal distances. The one nearest the 

 posterior end of the liver, situated at about the beginning of the 

 posterior third of the liver, arises by three roots from the parietes, 



* Hoclistetter, Morpli. Jahrb. xix., and supra p. 505 footnote. 



t See infra, p. 509. But in Sunectes (P. Z. S. 1906, vol. i. p. 21) we may find an 

 exception. It seemed to me that in tliis snake an affluent vein entered the kidney 

 as in OjpMsaurics (P. Z. S. 1905, vol. ii. p. 477), 



X Morph. Jahrb. xix. pi. xvi. fig. 14. 



