The spider has two body parts, the hard front, the head and the chest, called the cephalothorax or prosoma and the soft back, the abdomen, called the opisthosoma.
The stomach and the cephalothorax are connected to a thin waist called a pregenital pedicle or somite, a trait that allows the spider to move the stomach in all directions.
This waist is actually the last segment (somite) cephalothorax and is lost in most other members of the Arachnida (in the scorpion it is only detectable in the embryo). The spider has two palp (used for care and feeding) attached to the cephalicothax
All spiders have eight legs, though some ant-mimic species use their front legs to mimic the antenna, which is less the spider