Complex sentence: Sayellinae is a taxonomic subfamily of minute ectoparasitic sea snails, marine gastropod molluscs, or micromollusks, in the very large family Pyramidellidae, the pyrams and their allies.
Split into simpler sentences: Sayellinae is a taxonomic subfamily of minute ectoparasitic sea snails. These are marine gastropod mollusks, or micromollusks, in the very large family Pyramidellidae, the pyrams and their allies.