316 GEOGRAPHICAL AND GEOLOGICAL DISTRIBUTION. 



Gerrhonotus, passes beyond the fiftieth parallel ; in the Middle 

 United States the northern skink (Eumeces septentrionalis) pene- 

 trates into Minnesota, and along the Atlantic border Eumeces fas- 

 ciatus, a species, singularly enough, also found in Japan, forms 

 part of the Massachusetts fauna. The most southerly range of any 

 species is that of Liolsemus Magellanicus, which reaches the Strait 

 of Magellan. 



In the whole of Europe north of the forty-fifth parallel of lati- 

 tude, or what might be considered to be Central and Northern 

 Europe, there are scarcely more than a dozen species of lizard, of 

 which nearly one-half belong to the genus Lacerta, or common 

 lizard. Scandinavia, Great Britain, and Denmark have each three 

 (and the same) species: Lacerta vivipara, L. agilis, and Anguis 

 fragilis. An additional species, the wall-lizard (L. muralis), be- 

 longs to Belgium and Holland, and a fifth one, the green lizard 

 (L. viridis), which has also found a congenial home on the island 

 of Guernsey, to Germany. All of these species form part of the 

 southern or Mediterranean fauna, which in Europe comprises some 

 thirty-five or more species, many, or most of them, of a distinctively 

 African type. The affinities with the tropical faunas are seen in 

 the development of the geckotine type (Hemidactylus verruculatus, 

 the common gecko of the houses of Southern Europe ; Gymno- 

 dactylus, Phyllodactylus, Platydactylus) and the agamas (Agama, 

 Stellio South Russia and the Balkan Peninsula), the Old World 

 representatives of the American iguanas. One species of chamseleon 

 (Chamseleo vulgaris) is found in Andalusia. 



In temperate North America lizards are even more scarce than 

 in the equivalent region of the Old World. Indeed, in the whole 

 of the continent north of a line that might be considered to unite 

 San Francisco with Galveston in Texas there are probably less than 

 twenty species, of which more than one-half belong to the Old 

 World genus of skinks, Eumeces. A distinctive feature separating 

 the saurian fauna of this tract from the European is the absence of 

 the group to which all the commoner European forms (Lacerta) 

 belong, although the genus Xantusia, from the Pacific coast, is by 

 some authors doubtfully referred to the Lacertida3. On the other 

 hand, a distinct Old World relationship is established in the glass- 

 snake (Ophiosaurus from Tennessee southward and westward), a 

 near ally of which is the glass-snake (Pseudopus) of Southern Eu- 



