; class Reptilia, subclass Anapsida)
An order of reptiles in which the body is enclosed in a shell of bony plates covered by horny scales with an upper carapace and lower plastron. The carapace is often fused to the vertebrae and ribs. The jaws are toothless and horny. There are some 250 species, including marine, freshwater, and terrestrial forms.
Subjects: Zoology and Animal Sciences.