Wikipedia
Isospiridae
Isospiridae is an extinct family of fossil sea snails, Paleozoic gastropod mollusks.
This family is unassigned to superfamily. This family has no subfamilies according to the taxonomy by Bouchet & Rocroi (2005). It is classified as "Basal taxa that are certainly Gastropoda" by Bouchet & Rocroi (2005).