The late stage larvae of five common mytilid bivalves (Mollusca: Pelecypoda: Mytilacea) are described and provisionally identified asMytilus edulis aoteanus, Modiolus areolatus, Perna canaliculus, Xenostrobus pulex, andModiolarca impacta. All are readily distinguishable on the basis of larval shell features, including hinge structure. However, one common species,Aulacomya maoriana, was not discerned, and thus the identifications must remain tentative.