Siphons are tubular, muscular structures formed by partial fusion of the posterior mantle margins in many bivalves. The presence or absence of siphons differentiates dreissenids (zebra and quagga mussels) and Corbiculafluminea (Asian clam) in the pediveliger stage. Siphons are absent in the dreissenids at this stage, but are present in C.fluminea.
Zebra mussels develop an inhalant siphon (larger in photo) and exhalant siphon only after the pediveliger stage.
Larval Identification Information
Zebra Mussel Identification