1906.] ANATOMY OF THE OPHIDIA. 29 



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

 covirse of the vena cava posterioi% about midway from the anterior 

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

 auricle, is a bi-anch 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 Eunectes. I am not able, therefore, 

 at present to do more than suggest the homology which fvirther 

 facts may substantiate *. 



Anterior Abdominal Vein. — The condition of this vein in Python 

 sehce presents one feature of considerable interest. In an earlier 

 communication f I pointed out that the obsei-vations of Jacquart 

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

 Snakes that the anterioi- abdominal vein is directly connected 

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

 Lacertilia. In Eunectes (both E. murinus and E. notceus) 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 in 

 Python. Having examined Python sehce 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 in 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 thvis 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 Boidee generally come nearer to the common starting- 

 point of both Ophidia and Lacertilia is strengthened by this 

 observation. 



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 anterioi- 

 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 middle of the left 

 kidney. The tubes reunited behind the gall-bladder. The 

 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. 



