Diversity of Exumbrellar Surface in Jellyfish with Remarks on the Optical Property of a Microvillar Array

reduced the reflection of light with large incident angles, which potentially affected the visibility of the contour of the umbrella. Therefore, the microvillar array may serve functions comparable to those of the nano-scale nipple array in some other metazoans. Moreover, an uneven pitch (distance between the apexes of neighboring microvilli) in the microvillar array potentially enhances the anti-reflection property. Although the difference in reflection reduction was only slight, this may be an example of unevenness in real biological structures that enhances the functional properties of the nanostructure.