Specific patterns in the blue marginal spots were able to be used to distinguish between individuals. Two worms are pictured two weeks apart. Examples of identifying features in its margin are depicted above: 1(A) an unusually small spot in close proximity to a much larger one, followed by (B) a relatively large space. This individual also has two distinct spots between its pseudotentacles (C). 2 (D) two spots between pseudotentacles are not symmetrical, right one is slightly larger. (E) 3 large, spaced out spots followed by a larger gap (F) before another singular dot. Individual 1 is oriented with its head facing downwards, and individual 2 is oriented with its head in the top left corner of the images.