610 MR. F. E. BEDDARD ON THE [May 29, 



oesophageal ai^tery ; there is then a considerable gap nntil, on a 

 level with the anterior extremity of the liver, an artery arises 

 which closely accompanies the branches of the vertebral vein 

 already described, and supplies the liver and the stomach. There 

 is then a considerable gap until the oiigin of the three usual 

 arteries which supply the greater part of the alimentary tract. 

 The first of these is that supplying the stomach, spleen, and 

 commencement of the intestine ; the two which follow are so close 

 together that they may almost be said to arise in common. Of 

 these the csecal artery is the anterior. 



§ Summary of miore imjwrtant facts in the Vascular System of 

 Heloderma. 



As compared with other Lacertilia, the following facts in the 

 anatomy of the vascular system of Heloderma are particularly 

 noteworthy : — 



(1) The absence of any ductus Botalli between the cai-otid and 



systemic arches. Varanus (as well as some other 

 Lizards) agrees Avith Heloderma. 



(2) The origin of the anterior abdominab vein as a direct 



continuation of the ischiadic veins as in Varanu^s and 

 the Crocodilia. 



(3) The persistence of the foetal umbilical vein as an affluent 



of the postcaval vein, not in front of the liver as in 

 Snakes, but in the region of the liver as in Birds. It is 

 possible that F«r«;^^^6S agrees in this*. 



(4) The existence of anterior parieto-hepatic veins as in Snakes 



and certain snake-like Lizards, in addition to the usual 

 posteriorly developed veins opening, as in other lizards, 

 into the extremity of the right lobe of the liver. Here 

 also Varanus agrees with Heloderma. 



(5) The independence of the gastric portal system from the 



intestinal portal system. The veins of the stomach 

 either open directly into the liver, or by way of the 

 anterior abdominal vein f ; they do not join the portal 

 vein. 



(2) On the Venous System in the Genus Yaranus. 



■ The only notes hitherto published upon the venous system of 

 the genus Varanus relate exclusively to the species V. griseust- 

 Having made a careful dissection of this § as well as of two other 

 species, and having accumulated some notes upon a few facts in 



* Below, p. 611. 



t The connection of the gastric veins with the anterior abdominal vein is of 

 course also to be seen in the Crocodilia. 



. X Corti : De Systemate Vasorum Psammosauri grisei, 1847. — Hochstetter : 

 "Beitrage z. Entwicklungsgeschichte des Venensystems, &c.," Morph. Jahrb. xiv. 

 p. 464. The species is called V. arenarius, a synonj-m. — Beddard : "On the Venous 

 System in Certain Lizards," P. Z. S. 1905, vol. i. p. 447. 



§ Not the same individual described in the paper above quoted. ■ 



