It seems that trilobites did better in eras named after Wales. Trilobites were disappearing, but there were a lot of Crinoids. The Permian period closed out the Paleozoic and spelled THE END for trilobites. It lasted from 290 to 245 million years ago. By the way, it was named for Perm, a city in Russia, not Wales, which obviously was the problem for our segmented friends.
Trilobites are famous for their eyes.
They were the first organisms to show complex visual structures. Many trilobites had schizoachroidal eyes, consisting of arrays of calcite lenses. Their cephalons and pygidiums fit tightly together. I have seen trilobite earrings, but my ears aren't pierced. My wife understands my trilobite infatuation, but she won't wear bugs on her ears.