1898.] NATURAL SCIENCES OF PHILADELPHIA. 63 



THE GERRHONOTUS OF THE SAN LUCAN FAUNA, LOWER CALIFORNIA, 

 WITH DIAGNOSIS OF OTHER WEST AMERICAN SPECIES. 



BY JOHN VAN DENBURGH. 



A little more than two years ago, in a consideration of the rep- 

 tiles of Lower California, 1 I said that " Without larger series of the 

 other species than are at hand, the status of the Gerrhonoti from the 

 'Cape Region ' of Lower California cannot be satisfactorily deter- 

 mined. It seems probable, however, that they are distinct from the 

 more northern G. scincicauda, and are referable to the name G. 

 multicarinatus Blainv." More recently 2 I have been able to ex- 

 amine large numbers of specimens of the four species of this genus 

 which are known to occur in California, Oregon and Washington, 

 and to discover more or less definite limits to their variation. I 

 wish now to consider the status of the Lower Californian form. 3 



At first glance the lower Californian lizard bears a resemblance 

 to Gerrhonotus principis of the Puget Fauna. This, however, is 

 merely a superficial resemblance due to the comparative smoothness 

 of these two forms, and in a less degree to their similar size and the 

 occasional absence of complete dorsal color bands in the San Lucan 

 species. In the number of the longitudinal rows of its dorsal scales 

 this Gerrhonotus is similar to G. pahneri and G. burnettii. In 

 other characters, however, it approaches Gerrhonotus scincicauda, 

 to which I believe it is most closely related. 



The following table shows the variation in the several species of 

 those characters which seem to be of value in classification. The 

 figures indicate the number of specimens examined. 



From this table we may formulate a key which will serve to 

 identify most specimens : 



1 Proc. Cal Acad. Sci. (2), V, 1895, p. 119. 



J Occasional Papers, Cal. Acad. Sci., V, 1897, pp. 102-115. 



s In making this comparison I have had twenty six specimens from San 

 Jose del Cabo, Sierra El Taste, Sierra San Lazaro, Sierra Laguna and Mira- 

 flores. 



