nectopod

[nek-tuh-pod] /ˈnɛk təˌpɒd/
noun
1.
(in certain mollusks) an appendage modified for swimming.
Origin
1895-1900; < Greek nēktó(s) swimming (equivalent to nḗch(ein) to swim + -tos deverbal adj. suffix, with cht > kt) + -pod