SPECIFIC CHARACTERS OF BRITISH LIZARDS 83 



head scales (p. 86), the reader should endeavour to 

 draw it himself from memory, so as to familiarise 

 himself with the position of each scale. Then he 

 should turn to the description of the specific scaling 

 characters of each species and construct for himself 

 a line drawing of the head of each species. This is 

 even more important in the snakes than in the lizards, 

 for the field naturalist who is familiar with the scaling 

 of the heads of the adder and the ring-snake, can 

 identify a specimen from the head alone, and is 

 not misled by any considerations of size or colour. 

 Whether this is the best possible manner that could 

 be devised for classification, and whether weight should 

 not be given to other characters more than it is, are 

 questions which need not concern us here ; the point 

 is, that scaling arrangements are specific characters, 

 and as such should be known by every field naturaHst. 

 It is quite possible that originally the scales which 

 cover the bodies of lizards were all alike, but a glance 

 at one of the lizards of the present day will show that 

 considerable differentiation has taken place between 

 the scales of one part of the body and those of 

 another. The scales of the head, back, limbs, and 

 belly, have become different in shape, and in type of 

 arrangement. For this reason those who have been 

 responsible for making classifications of reptiles have 

 found it best to take these as their guide. That is to 

 say, the scaling becomes of the greatest importance in 

 the distinction of one species from another, and of one 



