Anatomy is a branch of biology and Medicine which studies primarily the internal structure and design of the structure of living things.
The decapod crustacean, such as a crab, lobster, shrimp or prawn, is made up of nineteen body segments grouped into two main body parts, the cephalothorax and the abdomen.
A horn is a pointed projection of the skin on the head of various animals, consisting of a covering of horn surrounding a core of living bone.
In anatomy, the atrium, sometimes called auricle, refers to a chamber or space.