116 MR. F. E. BEDDARD ON THE [MilJ 17, 



giA^es off at least one branch to the rectum. A little further 

 forward each vein certainly divides into two branches. These 

 branches are, on each side, a renal afferent and a component of 

 the anterior abdominal vein. Both afferent renals receive, as 

 usual, branches from the dorsal parietes. The two roots of the 

 anterior abdominal vein are unequal in size, that of the right 

 hand being considerably the less. It is important to note this 

 fact, since in Eryx conicus the left root of the anterior abdominal 

 vein is the only one which persists. The epigastric vein arises 

 from the anterior abdominal shortly after the junction of its two 

 roots. Eryx johni agrees with E. jaculus. 



It is a peculiarity of Snakes as contrasted with Lizards, that the 

 anterior abdominal is occasionally partly double, whereas in Lizards 

 it is single after the fusion of its two roots. In the Oolubrine 

 and Yiperine snakes, so far as my experience goes, the anterior 

 abdominal is usually single except at its extreme posterior end. 

 In Zamenis gemonensis the vein bifurcates posterioi-ly, and after 

 a very short course ends in minute branches in the fat-body. 

 In Causus rhombeatus the extent of the bifurcate region of the 

 anterior abdominal is not much greater ; for 8 inches intervene 

 between the opening of the anterior abdominal into the portal 

 and its bifurcation posteriorly, which is 2^ inches from the vent. 

 In Boa const7'ictor, on the other hand, there are 23 inches between 

 the vent and the fusion of the two anterior abdominals anteriorlj^, 

 which point is 10 inches behind the liver, and therefore less from 

 the point of union of anterior abdominal and portal *. 



In the Anaconda the double character of the anterior abdominal 

 vein has been already referred to. In one specimen of Eryx conicus 

 it was single throughout. In another it was partly double, as 

 was also the case with two individuals of Eryx jaculus. In 

 Python seh<B (where it is figured as partly double by Jacquart f) 

 the fluctuation of this vein between the single and double condition 

 was more plainly seen. Just in front of the gall-bladder the 

 vessel communicates with the gastric portal vein ; from this point 

 to two inches behind the gall-bladder it is single. Then for a 

 distance of 4| inches it is formed of two tubes lying side by side ; 

 these reunite, and finally again separate to form two tubes. 



In Eryx johni the vein appears to be single after the union of 

 its two posterior roots. 



Jacquart figures a somewhat different state of affairs in Python. 

 The anterior abdominal bifurcates posteriorly and communicates 

 with only one afferent renal directly as in the Anaconda. The 

 other branch only communicates indirectly (by means of small 

 veins) with the left renal afferent. Hochstetter J observes that in 

 Tropidonotus natrix and Coluber cescidapii there is no direct 

 connection between the abdominal and the renal afferent veins. 

 I can quite confirm this by the conditions observable in Zamenis 



* I did not ascei-tain this measnrement. 



t Ann. Sci. Nat. (4) vi. p. 321. t Morph. .Jahih. xix. p. 489. 



