n. plTetrabranchiata(Zoöl) 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.
Century Dictionary and Cyclopedia
tetrabranchiataAn order of Cephalopoda, named by Owen from the two pairs of gill-plumes, or ctenidial branchiæ. The nephridia are also two pairs; two viscericardiac orifices open upon the exterior; and the oviducts and spermducts are paired, but the left is rudimentary. There are many sheathed circumoral tentacles, not bearing suckers, two hollow eyes, two olfactory organs, no ink-bag, and a large many-chambered shell, straight or coiled. The order has included both ammonoid and nautiloid forms, but has also been restricted to the latter. They abounded in former times, as is shown by the immense number and variety of fossils, but are now nearly extinct. being represented by the pearly nautilus only. See also cut under nautilus.
Webster's Revised Unabridged Dictionary
NL. See Tetra-, and Branchia
Tetrabranchiata, Hyatt on the.
"More Letters of Charles Darwin Volume II" by Charles Darwin
TETRABRANCHIATA (= Schizosiphona, Tentaculifera).
"Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 6" by Various