Spider, Western AustraliaA spider belongs to the group of animals known as arthropods. This group also includes insects, crabs, centipedes, scorpions and worms. Spiders are invertebrates which means they don't have backbones, but exoskeletons ( just like insects) , where their skeleton is on the outside. Spiders belong to the Class Arachnida. They have eight legs and two main body parts, the cephalothorax and the abdomen. The cephalothorax which is viewed as the head and chest area combined, contains the spider's brain, poison glands and the sucking stomach. The other body part is the abdomen, which is located on the lower part of the body and contains the organs for breathing, silk production, food storage and reproduction. Both parts are connected by a narrow waist called the pedicel. The legs of a spider are located on the cephalothorax. The silk spinning glands on a spider are called spinnerets and are located at the tip of their abdomen. Not all spiders spin webs but all spiders have fangs, which ejects venom. Spiders have between 6-8 simple eyes and each eye has a lens and retina. The spider feeds by injecting poisons into its prey and then pouring digestive juices over the victim which breaks down tissues. The spider then sucks up the liquid by using the "sucking stomach". Spiders are oviparous which means that they produce eggs which hatch after leaving the body.