''Polybranchia'' may refer to:
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''Polybranchia'' (annelid), genus of polychaetes in the family
Spionidae
Spionidae is a family of marine worms within the Polychaeta. Spionids are selective deposit feeders that use their two grooved palps to locate prey. However, some spionids are capable of interface feeding, i.e. switching between deposit and sus ...
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''Polybranchia'' (gastropod), genus of sea slugs in the family Caliphyllidae
{{Genus disambiguation