_italica_ (_Coronella_), 197 Jacobson's organ, 73 _jaculus_ (_Eryx_), 147 Javelin Sand-Boa, 147 Key to the identification, 22 Kidneys, 80 Kufi, 257 Labial pits, 76 _Lacertilia_, 1 _lacertina_ (_Natrix_), 208 Ladder Snake, 194 Largest Snakes, 21 Larynx, 79 Lataste's Viper, 247 _latastii_ (_Vipera_), 247 _lebetina_ (_Vipera_), 257 Leopard Snake, 191 _leopardinus_ (_Coluber_), 191 _lineaticollis_ (_Tropidonotus tessellatus_, var.), 162 Liver, 81 Livery of the young, 38 Locomotion, 93 Long-nosed Viper, 249 _longissimus_ (_Coluber_), 187 Loreal pit, 75 Loreal region, 12 Lungs, 78 Lycodonts, 58 Lymph-hearts, 78 _Macroprotodon_, 212 _Macroprotodon cucullatus_, 213 _macrops_ (_Vipera_), 224 Marine Snakes, 92, 95 Markings, 29 _mauritanica_ (_Vipera lebetina_, var.), 259 Melanism, 39 Mental groove, 13 _meridionalis_ (_Vipera ammodytes_, var.), 253 Mimicry, 35 _modesta_ (_Contia_), 205 _monspessulana_ (_Coelopeltis_), 208 _montandoni_ (_Vipera ammodytes_, var.), 252 Montpellier Snake, 208 Mortality from Snake-bite, 133 _Mosasauria_, 1 _murorum_ (_Tropidonotus natrix_, var.), 154 _Natrix lacertina_, 208 _Natrix vulgaris_, 152 _natrix_ (_Tropidonotus_), 152 Neck, 9 Nematoda, 111 _Nerodia_, 152 Nervous system, 73 _neumayeri_ (_Coelopeltis monspessulana_, var.), 210 _niger_ (_Coluber longissimus_, var.), 188 _nigrescens_ (_Tropidonotus tessellatus_, var.), 162 Nocturnal Snakes, 93 Northern Viper, 230 Nostrils, 13, 74 Oesophagus, 79 Olfactory organ, 73 _Ophidia_, 1 _Opisthoglypha_, 4, 151 Organs of a sixth sense, 75 Orsini's Viper, 221 Oviparous Snakes, 86 Oviposition, 85 Ovoviviparous Snakes, 85 Pairing, 84 Pallas's Pit-Viper, 262 Parasites, 107 _Pelias berus_, 221 _Pelias dorsalis_, 234 Pelvic arch, 52 _persa_ (_Tropidonotus natrix_, var.), 154 _persicus_ (_Zamenis gemonensis_, var.), 172 _picturatus_ (_Tropidonotus natrix_, var.), 155 Pit-Vipers, 75, 262 Poison apparatus, 62 Poison fangs, 55, 62 Poison glands, 62 Poisons, 66 _prester_ (_Vipera_), 235 _Proteroglypha_, 4, 151 Protozoa, 112 _pseudaspis_ (_Vipera berus_, var.), 236 Pupil, 12 _Pythoninæ_, 4 _quadrilineatus_ (_Coluber_), 191 _quatuorradiatus_ (_Coluber_), 182 _quatuorlineatus_ (_Coluber_), 182 Rattle, 20 Rattlesnakes, 20, 103 Rattling, 103 Reflex movements, 106 Relation to man, 133 Renard's Viper, 227