The signature characteristic of ctenophores are the comb rows. Formed by plates of closely-spaced cilia that are fused at the bases, comb rows beat in a wave pattern that moves from the aboral to the oral end. This constantly shifting pattern of rising and falling comb plates is easily visible. Movement of a comb plate triggers the comb next in line to begin its stroke, which in turn leads to a sequential succession of strokes to form the wave. Each comb makes a rapid stroke in the direction of the aboral end, with a slower recovery to the upright position.
Comb jellies are the largest of all animals that utilize the beating of cilia for locomotion.
It doesn't stop there - with lengths up to 2 mm, ctenophore cilia are the longest of any known. Each single comb within a row is made up of several thousand cilia, and each row may have dozens of combs, so an individual ctenophore is endowed with many thousands of cilia. All adult ctenophores possess eight comb rows, which easily distinguish them from any other type of gelatinous animal. A strikingly beautiful shimmering rainbow pattern is produced by the defraction of light passing between the cilia. A sensory structure, the apical sense-organ, sits at the end opposite the mouth.