slipper lobsters have six segments in their heads and eight segments in the thorax, which are collectively covered in a thick carapace. the six segments of the abdomen each bear a pair of pleopods, while the thoracic appendages are either walking legs or maxillipeds. the head segments bear various mouthparts and two pairs of antennae. the first antennae, or "antennules", are held on a long flexible stalk, and are used for sensing the environment. the second antennae are the slipper lobsters' most conspicuous feature, as they are expanded and flattened into large plates that extend horizontally forward from the animal's head.