gastrotrich
noun
gas·tro·trich ˈga-strə-ˌtrik 
: any of a phylum (Gastrotricha) of minute aquatic pseudocoelomate animals that usually have a spiny or scaly cuticle and cilia on the ventral surface
Word History
Etymology
ultimately from Greek gastr- + trich-, thrix hair — more at trich-
First Known Use
1940, in the meaning defined above