Scaphandridae is for the moment monogeneric containing the genus Scaphander, Scaphander was previoulsy counded within Cylichnidae due to a heavy external shell. Super family Philinoidea order Cephalaspidea, within clade Euopistobranchia, whitin Heterobranchia. Formerly of Opisthobranchia. Good artcles to look into:
Article On the origin of Acochlidia and other enigmatic euthyneuran ...
Article A molecular phylogeny of the Cephalaspidea sensu lato (Gastr...
Article Systematic revision of the genus Scaphander (Gastropoda, Cep...
Article Unique digestive system, trophic specialization, and diversi...