CANALIS SEMICIRCULARIS
canalis semicircularis: translation
(plural canales semicirculares))
semicircular ear canal (fluid-filled canals embedded in the cranium and concerned with balance and hearing. Gnathostomata have 3 canals, lampreys have 2 (lacking a horizontal canal), and hagfishes have only one canal, perhaps appearing secondarily by the joining of two canals). Fossil Cyclostomata my have had 7 or more semicircular canals