Monhystera sp.

The family Monhysteridae is composed of a number of genera, including Monhystera, which live under marine conditions, in fresh-water as well as in dry soils; they even occur in mosses which regularly dehydrate and under anaerobic conditions in marine or freshwater sediment. Because they have a short generation time, about one week, and tolerance they can be easily cultivated under laboratory conditions.  As characteristic for opportunistic species, they are rather tolerant to pollutants.

The picture shows the head of a Monhystera with a large mouth surrounded by two rings of papillae and more posterior, on both body sides, an lateral organ called amphid.