SPECIFIC CHARACTERS OF BRITISH LIZARDS 85 



stand the general principle of their terminology, it is 

 necessary to take an instance of a head which exhibits 

 all the scales or shields which have special names. 

 Such a typical head is shown in the illustrations 

 here given. We shall see later which of these shields 

 are present, and which are wanting in our indigenous 

 lizards. 



We restrict our description to those shields only 

 which are most important for purposes of specific 

 distinction, the rest may be disregarded by the field 

 naturalist. 



The three surfaces of the head must be taken in turn. 



1. The Vertex. 



The shields which claim attention on the top of the 



head are the following : — 



{a) The frontal ; (h) the parietal ; (c) the 

 fronto -parietal ; {d) the pre - frontal ; (e) the 

 inter - parietal ; (/) the inter-nasal; (g) the 

 inter-fronto-nasal ; (A) the supra-ocular ; {i) the 

 occipital ; {j) the temporal. 



In addition to these, portions of the rostral shield, 



and of the nasal shields, may be visible from above ; 



the former, however, is, strictly speaking, anterior — not 



superior, and the latter belong more to the lateral 



or side view. 



Of those which are actually on the top of the head, 



the most important are the frontal, the parietals, the 



supra-ocular, and the pre-frontals. 



