This image is larva of the long-spined tropical sea urchin Diadema Antillarum, at day 32. The larva is ready for metamorphosis into the juvenile.
This image was captured using the Meiji MT4310 phase contrast microscope along with a Nikon D80 camera, connected to the microscope with the ND80 camera adapter. The image was captured using bright field at 400x magnification.