2 Lacertuhv. 



As in all classifications dealing willi a large number of 

 genera, these cannot be disposed in a linear series, and 

 one must therefore not be surprised to find Nurras and 

 Eremias, although nearly completely connected, placed 

 as Nos. 1 and 18 in the series, or Lacerta and T<ichii- 

 dromus, to which the same remark applies, as Nos. 2 and 

 11. What I believe to be the natural relationships of 

 each is mentioned in every case after the generic defini- 

 tion, and for the principles which have guided me in the 

 phylogenetic comments I must refer especially to the 

 remarks on Lacerta and Nncras, first published in 1916 

 (Tr. Zool. Soc. xxi) and 1917 (Ann. S. Afr. Mus. xiii), 

 and here reproduced, with slight alterations, after the 

 definitions of these two genera. 



Synopsis op the Genera. 



I. Ventral plates smootli ; collar strongly marked ; 

 digits not serrated laterally ; subdigital lamellae 

 smooth or tubercular, except in some specimens of 

 PMlochortus, in which they are keeled. 



Nostril pierced between two or three nasals, separated 

 from the first upper labial ; dorsal scales small, 

 juxtaposed . . . . . . . 1. N^icras, Gray. 



Nostril pierced between two or three nasals and the 

 first upper labial, or separated from the latter by a 

 narrow rim ; dorsal scales small or moderate, juxta- 

 posed or subimbricate ..... 2. Lacerta, Linn. 



Nostril pierced between two or three nasals and the 

 first upper labial, or separated from the latter 

 by a narrow rim ; dorsal scales large, imbricate, 

 strongly keeled ...... 3. Algiroides, Bibr. 



Nostril pierced between two nasals and the first upper 

 labial, or separated fi-om the latter by a narrow 

 rim ; back with two to six longitudinal series of 

 enlarged plate-like scales . . 4. PhilocJiortus, Matschie. 



