"R. Zweifel 1953 Journal 9 mi. N Mazatlan, 100', Sinaloa, Mexico July 16 Tonight we drove north on the highway a distance of 15 miles and back again. A Trimorphodon pancinacula, two Pitophis catenifer, two Rhinorhineus L. antoni and a large Impropetia dolata melanior were picked up on the road. All except one Rhinorhineus and the king snake were DOR. Hogler snakes have previously been reported from northern Sinaloa, so tonight's specimens constitute a range extension to the south. Today's minimum temperature 75°F, maximum 95°F. July 17 Broke camp today and moved to the beach. Went into Mazatlan for supplies. Bie justified our episteme by shooting one Juligosma today. July 18 At our camp on the beach 4 mi. N Mazatlan this morning I shot half a dozen Calliamaus. The lizards are abundant in the vicinity of thorny shrub and cactus patches just above the high tide line. The thorn forest here is lower (6-8") and much denser than that at our previous camp. Large amounts of cactus occupy what would in the other area have been relatively open ground beneath,