SWIMMERET
swimmeret, pleopod
(noun) one of the paired abdominal appendages of certain aquatic crustaceans that function primarily for carrying the eggs in females and are usually adapted for swimming
Source: WordNet® 3.1
Etymology
Noun
swimmeret (plural swimmerets)
(zoology) In decapods such as lobsters, one of the legs primarily used for swimming but also used for brooding the eggs (except in prawns) and catching food.
Synonyms
• pleopod
Source: Wiktionary
Swim"mer*et, n. (Zoöl.)
Definition: One of a series of flat, fringed, and usually bilobed,
appendages, of which several pairs occur on the abdominal somites of
many crustaceans. They are used as fins in swimming.
Source: Webster’s Unabridged Dictionary 1913 Edition