Turtle
Turtles are divided into two living suborders (groups): the Cryptodira and the Pleurodira. The Cryptodira is the larger of the two groups. All marine (sea) turtles, terrestrial (land) tortoises, and many of the freshwater turtles belong to this group. The Pleurodira are sometimes known as the side-necked turtles because of the way they hide their heads into their shells. This smaller group is mostly made up of freshwater turtles.