The above image shows a dorsal view of a preserved crayfish. Note that the cephalothorax of this decapod crustacean is covered by a tough carapace (5) that terminates anteriorly in a pointed rostrum (4). Behind the cephalothorax is the segmented abdomen (6) that terminates in an unpaired structure called the telson (13).  The telson along with the paired uropods (12) form the tail fan of the crayfish. Also observe the first two pairs of appendages, the antennules (1) and antennae (2), which are involved in such sensory functions as touch and taste and the large compound eye (3). As the name suggests, all decapods have five pairs of walking legs, the first of which are called cheliped (7) that are use to obtain food and for defense. The second (8), third (9), fourth (10), and fifth (11) walking legs are also visible. For close-up views of the anterior and posterior halves of the crayfish, click on the links  to the right:   Anterior Close-Up View     Posterior Close-Up View