Their skins are covered by a hard substance known as Chitin. This covering is called the Exoskeleton and helps to protect the organism
All arthropods undergo moulting a process whereby their exoskeleton is changed so that the organism can grow and a new exoskeleton is formed after growth
Their bodies are divided into 3 parts; the head, thorax and abdomen. In some classes, the head is fused with the thorax to form a Cephalothorax, example: Arachnida, Malacostra, Chilopoda and Diplopoda
They have an open circulatory system that is, they lack a circulatory system and blood flows through space called Sinuses
Gaseous exchange takes place through the body surfaces such as gills, trachea or book lungs.
They have sensitive organ such as; eyes, antennae
Some arthropods have the ability to produce sharp sounds, example: Crickets
