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 (Cœlopeltis), [208]