hydrus (Coluber), [160]

Hyoid apparatus, [42]

iberus (Tarbophis), [219]

Iguanognathus, [54]

Ilysiidæ, [4]

Immunity, [66], [71]

incertus (Tropidonotus viperinus, var.), [167]

Incubation, [88]

Intelligence, [101]