Seib, R. 1985 Santa Rosalía to Isla San Marcos, Baja California Sur, México 5 May San Marcos peak canyon town light-house beach san luegos San Bruno quite common. I was struck by the scarcity of vegetation, especially cacti, on the island. I was pleasantly surprised by the lack of large wasps which normally sting me while lantern walking. At dusk we began to lantern walk eastward into the canyon. It soon became apparent that Coleonyx variegatus was really abundant. This lizard is normally rare in the peninsula and I suspect a lack of competition and/or predators has resulted in a thriving island population. Phyllodactylus are also common on the ground, as well as rocks. Within 15 min Doris found the first snake: a beautiful adult Elaphe rosaliae was stretched across several large rocks. It never moved as we stared in wonder at this rarest of Baja serpents. When I picked it up it was completely