Revision of the Echini, Cambridge Mass., University Press, 1872-1874, classification, Echinodermata, sea urchins, Museum of Comparative Zoology, A collection of intricate microscopic structures showcasing various types of diatoms and radiolarians, each displaying unique patterns and textures. The figures are organized in a grid-like format, emphasizing their symmetrical forms and distinct geometric designs. Each specimen highlights the complexity of these microorganisms, portraying a blend of circular and ornate shapes that are characteristic of their species. The detailed illustrations provide a glimpse into the fascinating world of microscopic life, inviting viewers to appreciate the beauty found in these tiny organisms.