They got their name because they are similar to a crab.
the end of the crayfish by the telson the tail is the flipper.
Chelipeds
A crayfish is a crustacean that has a similar appearance to the shrimp. When referring to a group of crayfish you simply call them by the same name.
A crayfish is also called a crawfish. Colloquial terms include crawdads, mudbugs, and yabbies.
The rostrum is the part of the crayfish that is located between the eyes and the antenna. Rostrum is Latin for "beak" so the rostrum on the crayfish is considered its beak.
The function of a goldfish's tail is to move it around.
The crayfish has a pair of legs called chelipeds, more commonly known as pinchers. The joint motion of these pinchers allow the crayfish capture prey and defend itself.
Usually in New Zealand it is called crayfish but also known as rock lobster. There are two main species of crayfish (Koura) in New Zealand; the Spiny Crayfish or Koura Papatea (Jasus edwardsii) and the Packhorse Crayfish or Pawharu (Jasus verreauxi).
Lobsters that live in the land of Oz.
ganglia
Crayfish
It's called 'calcification'