Report on the zoological collections made in the Indo-Pacific Ocean during the voyage of H.M.S. 'Alert' 1881-2.London :Printed by order of the Trustees,1884. biodiversitylibrary.org/page/12067700
These crazy urchins seem to dominate the exposed regions of the mid-intertidal on Kauai. I wasn't really even sure what I was looking at when I first saw them, which is just about my favorite experience outdoors.