Turtles are reptiles and are internally similar to lizards and crocodiles.
However, several changes have occured to their body structures because of the development of shells. In order to describe the turtle's anatomy, I have divided the turtle into 7 systems - skeletal, muscular, digestive, respiratory, circulatory, excretory and reproductive, and nervous. The following diagrams and text describe these systems. Circulatory System Nervous System Sources Ashley, Laurence M. Laboratory Anatomy of the Turtle . Carl Petterson - Illus.