1907.] OF CERTAIN SPECIES OF SQUAMATA. 57 



communication *. In Gerrhonotus the splenic prolongation of the 

 pancreas is present, but it does not reach the spleen at all, though 

 extending a good way in the direction of that organ. Among 

 the Skinks this pancreatic pi^ocess towards the spleen is to be 

 found, as I have already recorded f, in the genus Tiliqua, and can 

 confirm in all details from a svibsequently examined example of 

 that genus. 



There is, however, no particular likeness in the structure of the 

 pancreas of Gerrho7iotus to that of Ojihisaurus %. In the latter 

 the pancreas consists only of two closely applied lobes which rest 

 upon the ventral surface of the pylorus and small intestine, there 

 is no vestige of a splenic lobe §. The spleen of Gerrhonotus is 

 I'ather peculiar in position. Very generally among the Lacei-tilia 

 this blood-gland is elongated and somewhat bean-shaped in out- 

 line, and lies with its long axis parallel with the long axis of the 

 stomach. In Gerrhonotus the shape is quite normal, but the long- 

 axis is perpendicular to the long axis of the stomach. 



The hepatic portal system of veins of Gerrhonotus cceruhus 

 varied but little in the two specimens dissected. The ventral 

 parieto- hepatic veins running in the umbilical ligament were 

 three in each Lizard. The first two crossed each in their course 

 in one specimen, and perhaps in both, though I have no note as 

 to this in the second example dissected. The crossing is such 

 that the anterior of the two vessels draws blood from a region of 

 the ventral body behind that which is supplied by the posterior 

 of the two veins. 



The dorsal parieto-hepatics are either two or three and are 

 otherwise quite normal in their position. The arrangement of 

 the gastro-hepatic veins is interesting in relation to the question 

 of the affinities of the genus Gerrhonotus. There are either four 

 or five of these vessels of somewhat varying calibre arranged close 

 together, and thus forming a ladder-like structure lying quite at 

 the anterior end of the liver and running to this from the adjacent 

 border of the stomach. There are no gastro-hepatic veins situated 

 more posteriorly. The interest attaching to this arrangement of 

 the vessels is that it is completely paralleled in Ophisaurus apus ||, 

 making allowances for the greater elongation of the liver in the 

 latter snake-like Lizard. 



In Ophisaurus, in fact, there are six of these veins. Now, as a 

 rule, the Lacertilia have not a great many separate gastro-hepatic 

 vessels. I have myself examined several species embracing as 

 many genera and find the following facts, some of which I have 



* Cf. pp. 48 & 55. t P. Z. S. 1905, vol. ii. p. 262. 



X In contrast to this difference in form between the pancreas of genera which 

 appear to be allied is the close resemblance in another case which I take this oppor- 

 tunity of recording. In both Iguana tiiherculata and Liolcemns magellanicus (I 

 owe the specimen to the kindness of my friend Capt. Richard Crawshay), which are 

 both Iguanidae, but not much alike superficial!}', the long splenic lobe of the pancreas 

 just touches the posterior end of the spleen. 



§ See P. Z. S. 1905, vol. ii. p. 475, text-fig. 64 jo. Angiiis also lacks the splenic 

 lobe. 



II See P. Z. S. 1905, vol. ii. p. 475, text-fig. 64. 



