Practice question

Ctenophora known as comb jellies recognized by eight longitudinal meridional rows of ciliary comb plates called ctenes composed of fused macrocilia stacked as transverse combs beating coordinated metachronal waves for ciliary locomotion through viscous propulsion rather than muscular pulsation. Plates diffract light producing iridescent effect. Each row forms effective paddle. Unique to phylum inspiring name cteno comb and phora bearing. Absent in cnidarians which employ muscular contraction. Some benthic ctenophores secondarily lost combs as adaptation to creeping lifestyle on substrate feeding on small plankton and benthic organisms with reduced swimming ability and altered morphology.