1906.] VASCULAR SYSTEM OF THE HELODERM. 605 



tliey are somewhat asymmetrical ; a fact which does not disguise 

 the resemblance which they bear in details to the corresponding 

 veins of Varanus. On the right side, the two veins which issue 

 from the leg are connected below the pelvic region by an anasto- 

 mosis whose calibre is as great or nearly so as that of the two 

 veins which it joins. The junction lies to the dorsal side of the 

 femoi'al artery which ci'osses it below. The more anterior of the 

 two veins, which I presume to be the sciatic, then bends upon 

 itself, but passes directly into the anterior abdominal vein, of 

 which it forms the right root. The other vein, the femoral, 

 receives the usual latei-al caudal vein a.nd joins the right bi-anch 

 of the caiidal, forming with it the renal afferent vein of the right 

 kidney. This junction takes place behind the kidney. The 

 ischiadic artery lies dorsal of this vein, and is crossed ventrally by 

 the conjoined femoral and lateral caudal. It appears from Hoch- 

 stetter's figure that the i^elative positions of these blood-vessels is 

 exactly the reverse in Varamos, that the artery is ventral of the 

 vein. On the left side of the body, the likeness to Va7'ami,s is 

 exhibited in a more striking way, since the junction of the veins 

 in the leg is more normal. The two veins of the leg unite with 

 each other, and shoi'tl}^ thereafter divide into the left i-oot of the 

 anterior abdominal vein and a branch joining the left renal 

 afierent vein behind its point of contact with the corresponding- 

 kidney. Just before this division the common trunk from the 

 leg receives the lateral caxidal. The arrangement of these various 

 veins is therefore exactly as in Varamos, and thus differs equally 

 from that prevalent among the Lacertilia. The anterior abdominal 

 is chiefly concerned with the blood returned from the fat-body, 

 from which it receives a considerable number of affluents. I 

 noticed only one branch from the fat-body to join the right root 

 of the anterior abdominal, the rest poured their contents into the 

 common trunk. 



The hepatic portal system of this Lizard is more complex than 

 that of many other Lizai'ds. In addition to the usual veins, 

 derived from the parietes and viscera, common to the Lacertilia as 

 a whole, there are, as will be seen from the following account, 

 certain veins which are not represented, or are I'arely represented, 

 in other genera of the Lacertilia, 



System of Vertebral Veins and branches to Liver. — It is the 

 rule among the Lacertilia for the azygos and the vertebi'al veins 

 and their bi-anches to the liver to be mainly developed upon the 

 right side of the body, and for the separate gastro-hepatic affluents 

 of the portal system to be independent not only of the main portal 

 vein, but also of the dorsal parieto-hepatic veins running from the 

 body- wall to the liver- substance. In these various particulars the 

 venous system of Heloderma is rather different fi'om that of other 

 Lizards, 



The Azygos Vein in Heloderma is short and to be found only 



