1906.1 ANATOMY OF THE OPHIDIA. 29 



sehce what I believe to be the remains of this vein. Along the 

 course of the vena cava posterior, about midway from the anterior 

 termination of the liver and the entrance of the vein into the 

 auricle, is a branch of the vena cava, which is of some thickness 

 and runs for a very short distance ventrally. Here its calibre 

 lessens abruptly, and it becomes continuous with slender veins 

 which run to the ventral parietes and are a part of the epigastric 

 system. It is the large size and the sudden alteration in the 

 calibre'of the part of this affluent of the epigastric which joins 

 the vena cava which lead me to infer that this end portion is the 

 persistent umbilical. It is, however, further away from the liver 

 than the umbilical vein is in Eimectes. I am not able, therefore, 

 at present to do more than suggest the homology which further 

 facts may substantiate*. . . „ i. 



Anterior Ahdomincd Fern.— The condition of this vein m Python 

 sebcB presents one feature of considerable interest. In an earlier 

 communication t I pointed out that the observations of Jacquart 

 as well as myself tended to show that it is only among the Borne 

 Snakes that the anterior abdominal vein is directly connected 

 with the renal afferent veins, as they always are among the 

 Lacertilia. In Eunectes (both E. murinus and E. notmts) it is 

 only one of the two roots of the anterior abdominal which is thus 

 connected, and that of the left side. The right origin of the 

 anterior abdominal is from a plexus of venules upon the gut. i. 

 quoted Jacquart to the effect that this also is the arrangement m 

 Python. Having examined Python sebce with great attention 

 in regard to this important matter, I am able to state that that 

 snake differs from Eunectes and agrees with Eryx jaculus m that 

 both roots of the anterior abdominal are connected each with one 

 of the two renal afferents. The veins in question can be easily 

 observed on dissection to lie dorsally of the forwardly-directed 

 rudiment of the pelvic arch, which thus conceals a portion of each 

 vein when seen after the serpent is opened in the usual way from 

 the ventral surface. Python, at least P. sehce, is therefore quite 

 Lacertilian in the disposition of these vessels, and the opinion 

 that the Boidfe generally come nearer to the common starting- 

 point of both Ophidia and Lacertilia is strengthened by this 



observation. . ,, j. 



In view of accumulating facts concerning the venous system 

 of Snakes, it is important to notice all variations so as to 

 arrive at the normal characteristics. I may therefore mention 

 that, as Jacquart and I have previously stated, the anterior 

 abdominal of Python sehce divided to form two tubes during its 

 course In the individual upon which I report here, the division 

 commenced at a point about opposite to the mif^^le of the left 

 kidney The tubes reunited behind the gall-bladder. Ihe 

 anterior abdominal, as in other individuals, unites with the 

 portal a little way in front of the gall-bladder It is to be 



* See below, p. 35. 



t P.Z.S. 1904.,. vol. ii. p. 116. 



