Blastoids are an extinct class of echinoderm, the same phylum as starfish. Like trilobites, blastoids went extinct at the end of the Permian.

While living, blastoids were attached by a long stalk to the ocean floor. Like many sessile creatures, they were particle feeders. The starfish like pattern faintly visible in this specimen is made up of five food grooves also known as ambulacra In the living blastoid, many brachioles were attached to the ambulacra..

The brachioles captured food particles and passed them to the mouth. They were long, thin, delicate structures which are not usually preserved.

If you look closely in the upper righthand area of this specimen you'll notice what looks like the tiny shell of a gastropod.

Though long extinct, blastoids are quite common as fossils.

Like the small whole ammonite this was part of an $8 fossil kit.

As you can see from the measurements, this specimen is fairly small, about the size of a nickel. Though this is typical of what you'll find in these fossil kits, some specimens were a bit larger, perhaps the size of a half dollar!.

Though this specimen is fairly flat, possibly due to compression, many are well rounded and had a conical, tubular or spherical shape. Still others had quite a variety of other shapes.

This is the backside of the blastoid , which I think actually looks more interesting stereoscopically.

It would be nice to have a stereoscopic picture of a living blastoid, but you'd have to go back to the permian for that!

Anyone for a real life Permian Park?