When I look at this photo, I want to scroll it down so I can see the top of the sand dollar. Somehow, it doesn't work well for me that the top section is cut off. You should play around with different photos of different sections of the SD. The texture of the sand dollar is very interesting to look at. Good color tones.
nice capture of the symmetry pattern. I'm not that crazy about the cropping choice though. I would have liked to see more of the pattern at the top center and the two left and right top arms are crowded too close to the edge of the frame.