Oh good. You shouldn’t have any trouble finding images on the web. I was helped in imagining them by a post from my friend Bev, at her old blog Burning Silo.
An earlier draft of the poem started with reproduction, and how the ability of sperm and egg to meet up, and full development to take place, in open water led to the purple sea urchin’s adoption by laboratory scientists for the study of sexual reproduction and development, which in turn led to the complete sequencing of its genome, which is how scientists learned about the genes for vision and pursued that line of inquiry. Fascinating stuff, but too much to fit into one lyric poem. And I realized that it was the critter’s spininess that I most identified with anyway.