Cryptodira

thumb|Skull of a cryptodiran turtle from the family Emydidae thumb|Dorsal view of skull and [[cervical vertebrae of a cryptodiran turtle from the family Emydidae. Not all cervical vertebrae are featured due to the dissection cut.]]

The Cryptodira ('''') are a suborder of Testudines that includes most living tortoises and turtles. Cryptodira is commonly called the "Hidden-Neck Turtles" or the "Inside-Neck Turtles". Cryptodira differ from Pleurodira (side-necked turtles) in that they lower their necks and pull the heads straight back into the shells, instead of folding their necks sideways along the body under the shells' marginals. They include among their species freshwater turtles, snapping turtles, tortoises, softshell turtles, and sea turtles.