The Reptilia include II species of the crocodile, alligator and lizard, including the savage jacare of the Amazon, several species of turtle, 4 species of batrachians, and 29 species of serpents, including the striped rattlesnake (Crotalus durissus), Lachesis mutus, and a rather rare species of Cophias.
The green rattlesnake (Crotalus molossus) inhabits the valley of the Rio Grande; the plains rattlesnake (Crotalus confluentus), the north-western counties; the diamond rattlesnake (C. adamanteus), the wooded river bottoms; the Texas rattlesnake, western Texas and the southern coast counties; the banded rattlesnake, a few widely separated woodland districts.
The ophidians are also very numerous, ranging from the comparatively harmless boa-constrictor to the deadly " palanca " or " fer de lance " (Lachesis lanceolatus) and rattlesnake (Crotalus), of which there are several species.