Lacerfa. 139 



1. Length from snout to vent (in luilliuietres). 2. Scales across middle of body. 

 3. Longitudinal series of ventral plates. 4. Transverse series of ventral plates. 

 5. Plates in collar. 6. Gular scales in straight median series. 7. Femoral 

 pores (right and left if differing). 8. Lamellar scales under fourth toe. 

 9. Anterior loreal (right and loft if differing). 10 Upper labials anterior to 

 subocular (right and left if diffei'ing). 



Distribution. — This species shares with Vijiera benis and Bona 

 temporaria the most northern distri])ution of all Palaearctic Reptiles 

 and Batrachians. Except for the absence of the Viper from Ireland, 

 these three species have roughly the same range, extending right across 

 Europe and Asia, from the extreme North of Scotland and Lapland to 

 the Amoor and the Island of Sachalien. The southern limit of its 

 distribution embraces the South of France, including the Pyrenees, 

 the continental part of Italy, Istria, Croatia, Bosnia, Herzegovina, 

 Bulgaria, Moldavia, Southern Russia from Podolia to the European 

 slope of the Caucasus and the Kirghiz Steppes, and from the latter to 

 the Altai, Northern Mongolia, L. Baikal, the Amoor, and Sachalien. 

 It attains the altitude of 2670 m. in the Pyrenees, 3000 m. in 

 the Alps and in Bulgaria, 2100 m. in Bosnia, 2400 m. in the 

 Transylvanian Alps. Generally distributed in the North, in woods, 

 lanes, meadows, and on heaths, sand-hills and cliffs near the sea ; in 

 the South it is more local in the plains, being found principally in 

 bogs, damp meadows, and rice-fields, or is restricted to altitudes 

 of at least 800 m. 



It is highly remarkable for a species with so wide a distrilmtion, 

 and living under such varied conditions of climate and soil, to show no 

 definable geographical races ; very variable in scaling and coloration, 

 the differences which have been adduced in favour of the establishment 

 of varieties are purely individual, as the large material on which the 

 above description is based amply shows. The specimens which depart 



