Laxus
Laxus is a genus of nematode worms from the subfamily Stilbonematinae of the family Desmodoridae. Like other members of this subfamily, they are covered by a layer of symbiotic sulfur-oxidizing bacteria, which in Laxus are coccoid in shape. They are distinguished from other stilbonematine genera by the finely-annulated somatic cuticle, thickened cephalic cuticle, small and coiled amphidial fovea, and lack of male structures. There are at least five species in the genus.

References 

Chromadorea genera
Chemosynthetic symbiosis
Taxa described in 1894