The Slate-Pencil Sea Urchin (Eucidaris sp) is a marine (saltwater) cidaroid.
The Slate-Pencil Sea Urchin is covered with spines for protection. The spines are thick and straight, with blunt tips, that look like lead pencils. The spines are called tubercles. They radiate around a central point – its beak-like mouth. There are also shorter secondary spines.