hollow and covered by cuticle. The head is completely retractable, and is covered by a set of neck plates called placids when retracted.

Kinorhynchs eat either diatoms or organic material found in the mud, depending on species. The mouth is located in a conical structure at the apex of the head, and opens into a pharynx and then an oesophagus, both of which are lined by cuticle. Two pairs of salivary glands