It is a suborder of primitive sea snails, marine gastropod mollusks.
These snails have mostly conically coiled shells in which the spire is typically low to moderate in height.
[1] J. Brookes Knight, et al., in the Treatise on Invertebrate Paleontology[1] divided the Trochina into five superfamilies: the Anomphalacea, Microdomacea, Oriostomatacea, Platyceratacea, and Trochacea, based on stratigraphic occurrence and features of shell anatomy without trying to extrapolate from molecular data.
Members of the Trochina are included in the vetigastropods although originally by Knight et al. in the Treatise, they were considered to be a suborder within the Archaeogastropoda.
[1] While this earlier approach may differ from more recent attempts, and may be no more phylogenetically accurate, it does provide a useful scheme for studying this group of animals.