DIET-ADOPTATIONS IN VARANUS NILOTICUS. i O 



row, having a width of only 8 nim. At the same time the pterygo- 

 idea of the latter are exceedingly much stouter, so that tliey, on a 

 level with the fixation of the columella cranii have a depth of 

 11, and a transversal thickness of 10 mm.,whereas the same mea- 

 surements of V. salvator are resp. about 7 and 7 mm. The 

 columella which, of course, is also stonter in V. niloticus, joins 

 in this lizard the pterygoideum further in front tlian in V. 

 salvator. In the latter the pterygoidea form at their anterior 

 end thin laminse hardly 2 1 /* mm. in thickness, while in V. 

 niloticus their least thickness anteriorly is 6 mm. and for 

 the most part it is 7 mm. Where the pterygoidea join the 

 palatina the median interspace is in V. salvator 19 mm. in 

 V. niloticus hardly half that much or 9 mm. In conformity 



Fig. 4. Palatal aspect of the skull of Varanus salvator 

 2 /a nat. siz. 



with this difference in the position of the pterygoid and 

 palatine bones in the two lizards the transverse bone has a 

 quite different direction. In V. salvator (conf. fig. 4) it is a 

 good deal longer, but more slender (7 x 3 mm.), and its 

 main direction from before and backwards diverges from the 

 median line although it curves inwards at the posterior end. 

 In V. niloticus (conf. fig. 3) it is shorter but very much 

 stouter (10 x 6 mm.) and in its main direction it converges 

 all the way towards the median line. The result of this is 

 that the interspace between the palatine and the transverse 

 bone, in the former case is 6 — 7 mm., in the latter only 

 3 — 4 mm. 



