Sea Urchin Small 320×313 Medium 640×625 Large 1024×1000 Download Tiff Original 2457×2400 | (5.6 MB) Description Sea urchin: the heavy projections are the spines; the long, slender ones are the tube feet. Keywords Echinoderm, Echinodermata, sea urchin, urchin Galleries Sea Urchins and Sea Stars Source: Buel P. Colton, Zoology: Descriptive and Practical (Boston:D.C. Heath & Co., 1903) 339