1904.] ANATOMY OF THE LACEKTILIA. 449 



Ventral Parieto-hejmtic veiiis, — These: veins as independent 

 veins are poorly developed in Varanus as compared with the other 

 types. There are at most three of them. The anterior corresponds 

 to a vein which seems to be a characteristic vessel and always 

 found in Lacertilia. But its distribution in Varanus is rather 

 different. In one specimen the vein is foi-med by two affluents, 

 one from the ventral parietes and the other from the stomach. 

 Concerning the second specimen I am rather uncertain, but inclined 

 to believe that there is also a connection with the mammary 

 and epigastric branch of the jugular- (see p. 448). In the second 

 specimen, moreover, this vein enters the liver in company with 

 the left epigastric. The second vein of this series is a medianly 

 situated vessel which does not enter the liver independently, 

 but is an affluent of the left epigasti'ic. A third vessel enters 

 the antei'ior abdominal vein near to its entry into the liver. 

 Hochstetter observes* : — " Dass die Venen der vorderen Brustwand 

 in der Sternalgegend nicht in dei Zweige mlinden, die als V. portae 

 secundariae aufzufassen sind wie bei Lacerta, sondern in die 

 vorderen Hohlvenen, findet in der Lage des Herzens und seiner 

 grossen Gefiisse bei diesem Reptil seine Erldiirung." I am 

 disposed myself to look upon the fact rather as indicative of a 

 resemblance to Tiliqua and Iguana^ which lizards, as has been 

 mentioned, also have communications between the anterior veins 

 and the portal system of the liver. 



Summary. 



Some of the more important new facts described in the fore- 

 going pages may now be briefly recapitulated. 



(1) While there is generally (? always) an inequality in size 

 between the two vense renales revehentes, Tiliqua is remarkable 

 on account of the very reduced size of the left vein. 



(2) While Iguana possesses three epigastric veins, two lateral 

 and a median, the la,st only is developed in Tiliqua. Varanus 

 has the lateral epigastrics which, as in Iguana, are connected 

 anteriorly with the jugulars, but (? in cori-elation with the absence 

 of a bladder) the median epigastric is at most rudimentary. 



(3) The intestinal portal systems of Iguana and Tiliqua differ. 

 In the former there are only two branches from the small 

 intestine, one of which joins the gastro-splenic trunk ; in the 

 latter there are three veins, all of which open sepai-ately into the 

 portal trvink. 



(4) In both Iguana and Tiliqua there is a superficial vein 

 lying beneath the skin but above the musculature and along the 

 middle line of the sternum, which enters the liver posteriorly and 

 appeaxs to be connected with the jugulars anteriorly. 



(5) Varanus has but one vein running from the stomach and 

 oesophagus directly to the liver (?'. e. not by way of the intestinal 



* Loc. clt. p. 4t57. 



