INTRODUCTION. 



The words of Cuvier, with which. Milne-Bdwards 

 headed his ' Eecherches zoologiques pour servir a 

 I'hisfcoire des Lezards,' the first scientific attempt to 

 deal with the Lacertidae, in 1828, remain appropriate 

 to this day : " La determination precise des especes et de 

 leurs caracteres fait la premiere base sur laquelle toutes 

 les recherches d'histoire naturelle doivent etre fondees." 

 But I feel sure neither of these great masters in the early 

 days of Zoological Science realized the extent of the 

 material needed to achieve such an object. 



I trust the descriptions in this book, with special 

 references to individual variations, so often left out of 

 consideration by systematists, or alluded to in a more or 

 less vague manner, as well as the tables giving precise 

 data concerning the extent of numerical variation in the 

 lepidosis, will prove of lasting value. Results derived 

 from such a vast material as it has been my privilege to 

 examine, far surpassing any ever brought together before, 

 should be worthy of the attention even of those workers 

 in the same field who would disagree with the manner in 

 which they have been utilized in the elaboration of this 

 monograph. 



Recent attempts at multiplying species by the use of 

 characters which can be shown to be untenable when 

 sufficient series of specimens are available, are only to be 

 set right by the course here followed ■; it is besides of the 

 greatest importance, from the phylogenetic point of view. 



