CONTENTS Xlll 



Family Helodermatidae 73 



Genus Heloderma 73 



Family Xantusiidae 73 



Genus Xantusia 73 



Family Teiidae 74 



Genus Cnemidophorus 74 



Family Scincidae 79 



Genus Leiolopisma 79 



Genus Eumeees 80 



Genus Neoseps 83 



Family Amphisbaenidae 83 



Genus Bipes 83 



Genus Rhineura 84 



Suborder Serpentes 84 



Family Leptotyphlopidae 84 



Genus Leptotyphlops 84 



Family Boidae 85 



Genus Lichanura 85 



Genus Charina 86 



Family Colubridae 87 



Genus Carphophis 87 



Genus Abastor 88 



Genus Faraneia 88 



Genus Diadophis 88 



Genus Heterodon 91 



Genus Liopeltis 92 



Genus Opheodrys 93 



Genus Coluber 93 



Genus Salvadora 97 



Genus Phyllorhynchus 97 



Genus Elaphe 98 



Genus Drymobius 101 



Genus Drymarchon 101 



Genus Arizona 101 



Genus Pituophis 102 



Genus Rhadinea 105 



Genus Lampropeltis 105 



Genus Stilosoma Ill 



Genus Contia Ill 



Genus Cemophora Ill 



Genus Rhinocheilus 112 



Genus Sonora 112 



Genus Fieimia 113 



Genus Hypsiglena 113 



Genus Chilomeniseus 114 



Genus Natrix 114 



Genus Seminatrix 118 



Genus Storeria 118 



