Water Reptiles of the Past and Present

by Samuel Wendell Williston

CRYPTODIRA

The chief families of the Cryptodira turtles are the Chelydridae, or snappers; the Emydidae, or marsh tortoises; the Testudinidae, or land tortoises; the Chelonidae, or sea-turtles; the Protostegidae, or ancient sea-turtles; and the Dermochelydidae, or leather-backs. Other doubtful or smaller groups, both living and extinct, may be omitted, or incidentally mentioned.