A pair of cervical papillae or deirids are found in many parasitic nematodes at the level of the nerve ring. These and other sensory papillae are found along the body length of many nematodes. Caudal papillae (Figure 22.15) are very elaborate in males and help in copulation. Distribution of caudal papillae is an important taxonomic feature.
Phasmids (Figures 22.16 & 22.17) are found in some species. These are similar to amphids, but have fewer nerve endings. If a gland is present, it is smaller than those found in amphids.