What are the deep furrows extending from mouth to tips of each arm on a star fish called?

The deep furrows extending from the mouth to the tips of each arm on a starfish are called ambulacra. These furrows contain tube feet, which are used for locomotion, feeding, and sensing the environment. The tube feet are lined with cilia, which help to move water and food particles into the mouth. The ambulacra are also used for defense, as the starfish can use them to grip onto prey or predators.