Leatherback Turtle by Haeckel
Date 1904
Source Commons https://commons.wikimedia.org/wiki/File:Haeckel_Chelonia.jpg
Author Ernst Haeckel (1834–1919)   
Source: https://commons.wikimedia.org/wiki/File:Dermochelys_coriacea_Haeckel.png

The leatherback sea turtle (Dermochelys coriacea), sometimes called the lute turtle or leathery turtle, is the largest of all living turtles. It can easily be differentiated from other modern sea turtles by its lack of a bony shell, hence the name. Instead, its carapace is covered by skin and oily flesh.