The Biology and Anatomy of: The Starfish, types of star fish, color of starfish, Sea stars facts.

We begin by examining the starfish external anatomy, noting the pentaradial symmetry with five or more arms radiating from a central disk. The starfish aboral surface, or top side, features overlapping plates that can be smooth, granular, or spiny. Conversely, the starfish oral surface, or underside, contains the mouth.