How many departments does the crayfish body consist of?

The crayfish body consists of two sections.

1. Cephalothorax. It contains:

a pair of eyes;
long antennae – organs of touch;
short antennae – organs of smell and balance;
mouth organs – jaws and legs:
walking legs – 5 pairs, the first has changed into pincers.

2. The abdomen, consisting of 6 segments, the 7th has changed into a caudal fin. All segments of the abdomen, except for the last one, have abdominal legs. They constantly move and drive water under the carapace of the cephalothorax, where the gills are located.