The head and thorax of the shrimp are fused to form the cephalothorax and a narrow abdomen. There is a shell present that protects the cephalothorax. The shell is hard and thick in nature. This hell is harder than any other shell present on the body of shrimp. This is called the carapace. The carapace of the shrimps are found to surround the gills. Water is pumped through the gills by the action of the mouthparts. The carapace gives rise to the rostrum, eyes and whiskers. The word rostrum comes from the Latin word  “rostrum” which means beak. The rostrum of the head of a shrimp looks like a beak. It is pointed and is present at the front of the shrimp’s head. The shrimp uses the rostrum to attack for attack or defense. It is an extension that is rigid and placed forward of the carapace. It is also used by the shrimps to stabilise themselves and maintain balance while swimming.