A Revision of the Lizards of the Genus Tachydromus. 



By G. A. BoulEnGEr, LL.D., D.Sc, F.R.S. 



(Published by Permission of the Trustees of the British Museum). 



[With plates XLVI and XI,VII]. . 



INTRODUCTION. 



The species of Tachydromus , a genus of L-acertidse characteristic of the Far East, 

 and the only one of the family to extend eastward of the Bay of Bengal, are much 

 in need of revision. A number have been described since the publication of the 

 third volume of the British Museum Catalogue of Lizards, in which, owing to insuffi- 

 cient material, I united several that have since proved to be perfectly valid. The 

 importance to be attached to various characters, such as the number of rows of 

 plates along the back and belly, of inguinal pores, and of chin-shields, has often been 

 exaggerated and has led to the establishment of species which seem to be untenable. 

 My object in giving very detailed descriptions, with notes on individual variations, 

 accompanied by tabulations of the numerical characters in the extensive material now 

 at my disposal, 1 is to convey a clearer view of the state of things and thus to enable 

 future workers to form a more correct idea of the value to be attached to these 

 characters. I trust to have succeeded in avoiding the two extremes into which pre- 

 vious authors have fallen, viz. of over- multiplying species and of underrating the im- 

 portance of certain modifications which may appear trivial at first. 



Although generally averse to the multiplication of generic divisions, I feel com- 

 pelled to propose two new genera for species previously described under Tachydromus, 

 viz. T. dorsalis, Stejneg., and T. kuehnei, Van Denb., the former differing in the more 

 normal dorsal lepidosis, the latter in the form of the digits, unique in the family 

 Lacertidse. 



I have also to offer a suggestion as to the exact relationship of Tachydromus, 

 which has been regarded as occupying a very isolated position in the family to which 

 it belongs. The northen species T. amurensis , Peters, shows it to be much nearer to 

 Lacerta than was hitherto believed, as I explain in my comments on that species, 

 which differs so much from T. sexlineatus , Daud., the type of the genus, and stands 

 at the other end of the series. 



Tachydromus, Daud. 



Tachydromus, 1 Daud. Hist. Rept. iii, p. 251 (1802) ; Wagl. Syst. Amph., p. 157 (1830) ; Wiegm. 

 Herp. Mex., p. 10 (1834) ; Dum. et Bibr. Erp. Gen., v, p. 155 (1839) I Gray, Cat. Liz., p. 52 

 (1845) ; Giinth. Rept. Brit. Ind., p. 69 (1864) ; Lataste, Ann. Mus. Genova (2) ii, 1885, p. 

 125 ; Bouleng. Cat. Liz., iii, p. 3 (1887), and Faun. Ind., Rept., p. 168(1890). 



Tachysaurus, Gray. I.e. 



1 158 specimens, from a great variety of localities. ;2 Originally Takydromus, contrary to classical usage. 



