A Leidy's comb jelly, Mnemiopsis leidyi, off the coast of New Jersey, USA. About two inches wide, comb jellies range from Cape Cod to the Carolinas and are common in the Chesapeake Bay as far north as Baltimore. They have eight moving comb plates that move food toward the mouth. Marine labs use them to study bioluminescence and regeneration. Comb jellies are not true jellyfish. They have no stinging cells.