4. Tropidonotus tessellatus, Laurenti--The Tessellated Water-Snake 160 5. Tropidonotus viperinus, Latreille--The Viperine Water-Snake 165 Genus ZAMENIS, Wagler 170 6. Zamenis gemonensis, Laurenti--The European Whip-Snake 170 7. Zamenis dahlii, Fitzinger--Dahl's Whip-Snake 177 8. Zamenis hippocrepis, Linnæus--The Horseshoe Whip-Snake 179 Genus COLUBER, Linnæus 181 9. Coluber quatuorlineatus, Lacepède--Aldrovandi's Snake 182 10. Coluber dione, Pallas--The Dione Snake 185 11. Coluber longissimus, Laurenti--The Æsculapian Snake 187 12. Coluber leopardinus, Bonaparte--The Leopard Snake 191 13. Coluber scalaris, Schinz--The Ladder Snake 194 Genus CORONELLA, Laurenti 196 14. Coronella austriaca, Laurenti--The Smooth Snake 197 15. Coronella girondica, Daudin--The Southern Smooth Snake 202 Genus CONTIA, Baird and Girard 205 16. Contia modesta, Martin--The Dwarf Snake 205 Genus COELOPELTIS, Wagler 207 17. Coelopeltis monspessulana, Hermann--The Montpellier Snake 208 Genus MACROPROTODON, Guichenot 212 18. Macroprotodon cucullatus, I. Geoffroy--The False Smooth Snake 213 Genus TARBOPHIS, Fleischmann 216 19. Tarbophis fallax, Fleischmann--The Cat-Snake 217 20. Tarbophis iberus, Eichwald--The Caucasian Cat-Snake 219 Fourth Family: VIPERIDÆ Genus VIPERA, Laurenti 221 21. Vipera ursinii, Bonaparte--Orsini's Viper 221 22. Vipera renardi, Christoph--Renard's Viper 227 23. Vipera berus, Linnæus--The Northern Viper, or Adder 230 24. Vipera aspis, Linnæus--The Asp Viper 239 25. Vipera latastii, Bosca--Lataste's Viper 247 26. Vipera ammodytes, Linnæus--The Sand-Viper, or Long-Nosed Viper 249 27. Vipera lebetina, Linnæus--The Blunt-Nosed Viper, or Kufi 257 Genus ANCISTRODON, Palisot de Beauvois 261 28. Ancistrodon halys, Pallas--Pallas's Pit-Viper 262 Index 265 LIST OF PLATES PLATE FACING PAGE