The highly kinetic skulls of lizards, snakes, and worm lizards allow them to eat larger prey because of their large gape. Males in this order have hemipenes which are a pair of reproductive organs that are inverted until it is time for mating. Even though there is a pair, only one (hemipenis) is inserted into the cloaca. Order Squamata is the largest order of reptiles, and the third-largest order of vertebrates.