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Images: Shellfish's Mysterious Pathways to Adulthood

Working hard on a day most people would like to spend relaxing by the beach, MIT/WHOI graduate student Christine Mingione rinses a plankton sample from a collection screen into a bottle. She will take the samples back to the lab to count the larvae and image them using polarized light. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)

It's hard to tell the difference among early larval stages of various shellfish. But under polarized light, different species of larvae show different birefringence patterns, based on the crystal orientation of the calcium-containing minerals that make up their shells. Later-staged larvae begin to have body shapes that makes them easier to distinguish. 

Adult bay scallops use their adductor muscle to open and close their shells rapidly ... and swim. No other type of bivalve is able to swim. Scallops swim to escape predators. Tentacles around the shell opening help filter water through the opening to catch particles for food. Many silvery eyes line the outer edges and help the scallop sense light and movement. (Public domain)