28 MR. F. E. BEDDARD OX THE [Jan. 16, 



and Eunectes * I have described a vein running along the sperm- 

 duct and receiving branches from the parietes which are the 

 equivalents of the supra-renal portal vessels of other Reptiles. 

 This vein in the two genera mentioned is no doubt the equivalent 

 of a vein described and figured by Hochstettei- in Varanus t 

 which also accompanies the sperm-duct. In both AmphisbcBua 

 and Eunectes, as it appeared to me, the vein gradually died away 

 anteriorly and arose posteriorly from the substance of the kidney, 

 being not in any direct communication with any of the principal 

 longitudinal veins of the body. It appeared to me nevertheless 

 to be probably the homologue of the posterior cardinal veins of 

 the embryo, diminished in size and functionally replaced by the 

 renal eflerent veins or vense cavje posteriores or infei-iores. It 

 was the general relations of this vein on either side to the 

 mesonephric region and to the parietes which led to this opinion. 

 The conditions which obtain in Python sehce amply confirm this 

 point of view, and, as I think, settle the matter as certainly as it 

 can be settled in the absence of embryological data. 



The surface of the kidney shows in this specimen the course of 

 the various vessels which traverse it in the clearest fashion. The 

 single renal arteiy comes to lie on the kidney close to the anterior 

 end, and can be traced back beyond the kidney to the ureter. 

 The efferent renal vein begins quite near to the posterior end of 

 the kidney, and runs forward, increasing in volume. It is quite 

 distinct, of course, from the afferent renal, which runs not only 

 to the extreme anterior end of the kidney, diminishing in volume 

 as it proceeds, but is continued beyond ; it becomes, in fact, the 

 vein which I have already spoken of as the probable equivalent 

 of part of the posterior cardinal. The anatomical facts which 

 have just been detailed seem to me to prove that this inter- 

 pretation of the vein is the just one. It is quite possible that 

 the examination of rather better matei-ial of the two genera to 

 which I have referred in comparison with PytJion might show a 

 continuity in their case also. In any case it is quite obvious in 

 Python sehce and beyond the possibility of error. The only 

 instance of this forward extension of the afferent renal in another 

 snake [Zamenis gemonensis) has been recorded by myself i, where, 

 however, it is short and plunges at once into the body-wall, this 

 portion being, of course, the equivalent of the pai-ietal branches of 

 Python and Eunectes. 



Umbilical Vein. — -I have pointed out that in Eunectes the 

 umbilical vein is not merely a vein of the foetal circulation, but 

 that it persists in the adult, at least in Eunectes mu7'inus, whei'e 

 I noted the existence of the vein before the study of the newly- 

 born Eunectes notceus enabled me to fix its homologies. It 

 becomes, therefore, a matter of interest to enquire how far this 

 vein is represented in other Snakes. I have found in Python 



* See above p. 21. 



t Morph. Jahrb. xix. 1892, pi. xvi. fio:. 17. 



X p. Z. S. 1904, vol. ii. p. 117. 



