This color-changing function is produced by groups of red , yellow , brown , and black pigmented chromatophores above a layer of reflective iridophores and leucophores , with up to NUMBER@1 of these specialized pigment cells per square millimeter .

This color-changing function is produced by groups of red , yellow , brown , and black pigmented chromatophores above a layer of reflective iridophores and leucophores , all of these being parts of the cuttlefish 's skin which help it change its color . There are up to NUMBER@1 of these special pigment cells per square millimeter .
