1906.] VASCULAR SYSTEM OF YARANUS. 617 



supported by a fold, of membi-ane which attaches the " Hohlvenen- 

 foi-tsatz " of the liver to the parietes and forms a pocket as in 

 Iguana and some other Lizai'ds, including ^eZofZer«^a. The single 

 vein is not, however, a generic character of Varamcs. It is single 

 in V. exatithematicios and in V. ocellatus ; but in two out of four 

 examples of Varanus niloticus which I have dissected the 

 conditions were different. In two small specimens there was only 

 a single vein as in other species ; in one large individual there 

 Vv^ere distinctly two veins, which reached and penetrated the liver 

 separately ; in the fourth specimen, also large, and a female like 

 the last, there were also two veins, which, however, joined soon 

 after their emergence from the parietes to form a single trunk 

 entering the liver as such. In the two small individuals which 

 were males (and not very well preserved in sjoirit) it seemed to me 

 that there M^as a junction between two veins quite close to the 

 body-w^all. The more prevalent arrangement among the Lacertilia 

 is that there are several of these veins * running a parallel course 

 to the liver. 



In addition to this vein (or, rarely, veins) the liver also receives 

 blood from the dorsal or dorso-lateral parietes in its anterior 

 region. In Varanus griseus Hochstetter has mentioned a vein — 

 " eine Zweite Leibeswandvene dringt direkt in die kopf warts 

 gerichtete Spitze des rechten Leberlappens, diese wurzelt in der 

 entsprechenden Partie der dorsalen Leibeswand " f. There is no 

 further description of the vein. The vein in question is 

 accurately described by Hochstetter as entering the very tip of 

 the right lobe of the liver. It corresponds exactly in position to 

 a vein from the stomach which enters the tip of the left lobe %. 

 The origin of the vein from the parietes is of some interest. It 

 originates in fact from a longitudinal vein, the lateral abdominal, 

 whose relations to other veins has been already described. The 

 same vein occurs in Varanus niloticios, where I found it fuller 

 than in the example of V. griseus. The same vein plainly exists 

 in V. exanthematicus, with the same connections with the vein of 

 the dorso-lateral parietes. 



The existence of these venous affluents of the portal system is 

 of interest in comparing Varanus with other Reptiles. In the 

 presence of vessels from the dorsal parietes joining the liver- 

 circulation anteriorly as well as posteriorly, Varanus differs from 

 Lacerta, Iguana, and some other Lacertiha. It agrees, however, 

 in this with Heloderina, as has been already set f oi'th in the present 

 communication§. The connection, however, in this latter instance 

 is with the vertebral vein, while in Varanus the hepatic affluent 

 in question is only indirectly connected with the vertebral vein 

 system, and arises directly from the lateral abdominal vein, which 



* I may take this opportmiity of referring to another character which I have 

 found only in one species, and not in a considerable number of others. In Y. gouldi 

 the apex of the heart has a gubernaculum tying it to the pei-icardium. This is 

 generally stated to be absent, and I have not found it in V. bengalensis, V. griseus, 

 v. niloticus, and F". exanthematicvs. 



t Zoc. cit. p. 466. X ^- infra, p. 618. § V. supra, p. 606. 



