Macomona (tellins)
Macquariella (winkles)
Macroschisma (keyhole-limpets)
Macteola (false-turrids)
Mactra (trough-shells)
Madrella (sea-slugs)
Malluvium (bonnet-limpets)
Maoricolpus (screw-shells)
Maoricrypta (slipper-limpets)
Marikellia (leptons)
Marinula (air-breathers)
Marioniopsis (sea-slugs)
Marita (false-turrids)
Melanella (urchin-snails)
Melanochlamys (sea-slugs)
Melibe (sea-slugs)
Melliteryx (leptons)
Merelina (rice-shells)
Merisca (tellins)
Mesoginella (margin-shells)
Mesonychoteuthis (squids)
Mesopeplum (scallops)
Metaxia (dextral-creepers)
Microcolus (tulip-shells)
Microdiscula (orbitestellids)
Microdryas (false rice-shells)
Microgenia (false-turrids)
Micromytilus (micromussels)
Microvoluta (volute-mitres)
Midorigai (sea-slugs)
Mimachlamys (scallops)
Miralda (pyramid-shells)
Mitra (mitres)
Mitrella (dove-shells)
Mitromorpha (false-turrids)
Modiolus (horse-mussels)
Monophorus (sinistral-creepers)
Montfortula (notch-limpets)
Moroteuthis (squids)
Mucrosquama (chitons)
Munditia (liotias)
Muricopsis (murex-shells)
Musculista (mussels)
Musculus (bag-mussels)
Myadora (myadoras)
Myllita (myllitas)
Myochama (myochamas)
Myrtea (lucines)
Mysella (leptons)
Mysticoncha (ear-cowries)
Mytilus (mussels)