Nemathelminthes

noun plural

Nem·​a·​thel·​min·​thes -ˌthel-ˈmin(t)-(ˌ)thēz 

in some classifications

: a phylum including the nematodes and horsehair worms and sometimes the acanthocephalans, rotifers, gastrotrichs, and minute marine organisms of a related class (Kinorhyncha) which are all more or less wormlike animals with a cylindrical unsegmented body covered by an ectoderm without cilia that secretes an external cuticle