When talking about a turtles size, you will often come across the term “SCL”. SCL stands for “Straight Carapace Length”. Since the carapace (the top domed part of the shell) is generally curved to come extent, simply measuring the actual domed shell would give you a measurement longer than the actual turtle. Therefore placing the turtle next to a flat measuring tape and viewing the measurement from above (where the carapace seems flat) will give you the true length of the turtle, or the straight carapace length (SCL).