205 



to exist in any other Lacertilian nor is it found in all the Monitors. 

 I have found this network only in V. salvator. In Alligator 

 1 u c i u s ' ) there is something of the kind , but the network of bile 

 ducts is far simpler. 



3) A third peculiarity of the Monitor Lizards concerns the blood- 

 vessels of the neck, which, according to van Bemmelen^), distingui- 

 shes these Lizards from all others. In the particulars to which van 

 Bemmelen refers the Monitors are more aberrant than even Hat- 

 teria. 



4) Another feature in the anatomy of the Monitor es seems to 

 have attracted but little attention. It is characteristic of the follow- 

 ing species: — Monitor gouldi, Varanus salvator, V. ni- 

 loticus, V. griseus. On cutting through the abdominal parietes 

 of any one of these species , the viscera are not at once brought into 

 view; they are concealed by a fold of peritoneum, which forms a 

 tough membrane; this fold of peritoneum comple tely en- 

 circles the abdominal viscera, including the liver; it is 

 free ventrally and attached to the middle line dorsally; 

 it forms a shut sac separating the abdominal viscera 

 from the heart and lungs. The only description which I can 

 find of this structure is by Martin ^), who says „The chest is divided 

 from the abdomen by a partial membranous diaphragm attached to 

 the parietes of the abdomen by numerous strings . . . the liver lies 

 .... below the diaphragm . ." 



Brücke refers to the „diaphragm" of Varanus incidentally in 

 his paper *) recording the discovery of muscular fibres in the perito- 

 neum of that Lizard. Nowhere however is there any mention of the 

 fact that this structure is peculiar to the Moni tor es: it is not, so 

 far as my observations go, found in any other genus of the I^acer- 

 tilia vera^); nor is there any comparison of it to a structure in the 

 Crocodilia which is, in my opinion, homologous with it. This latter 

 has been described by most of those who have concerned themselves 

 with the anatomy of the Crocodilia including Sir Richard Owen^) 



1) 'Beonn's Tierreich'. Reptilien, Taf. C Fig. 4. 

 ; 2) Zoolog. Anzeig. Yol. X (1887). 



3) Proc. Zool. See. 1830—31, p. 138. 



4) Wiener Sitzungsber. 1852. 



5) I believe that I shall be able to show later that this fold of peri- 

 toneum is found in Chamaeleons. 



6) Proc. Zool Soc, 1830—31, p. 139. 



