The young are born blind with a covering of small spines.

The legs are of medium length and wear small spines.

Tail slightly broader than long, ending in a small spine.

There are small spines on the arms which lie flat against the surface.

Living sand dollars have small spines covering its entire body.

The skin is velvet black or dark brown, with numerous small spines on the lower part of the head and body.

The skin is a uniform dark brown with small spines throughout.

While the winter and spring forms have a small spine at the end of the body, the summer form often lacks it.

The strong stems have few branches and are covered in small spines.

The small spines at the end of the tail are not visible in flight.