Definition of "tetrabranchiata" []

• An order of Cephalopoda having four gills. Among living species it includes only the pearly nautilus. Numerous genera and species are found in the fossil state, such as Ammonites, Baculites, Orthoceras, etc. (noun-plural)

Gnu Collaboartive International Dictionary of English: licensed under The Code Project Open License (CPOL)