CN Cuticular nubbin (S) Ciliary cap (S) A very short lateral projection from the cilium of some sensory dendrites ( CEP, OLL, OLQ, ADE) that embeds into the inner cuticle layer, presumably anchoring the cilium to the cuticle. The nubbin material is apparently an extracellular secretion from the cilium and is somewhat electron dense, but generally does not produce an external bump (papilla) on the surface of the animal. These sensory endings sometimes are open through the cuticle, but are more often closed ( Perkins et al., 1986). See Papilla