If percussion is resorted to, the animal's chest will give a tympanic, drumlike sound.
"Special Report on Diseases of Cattle"
U.S. Department of Agriculture J.R. Mohler
Exception is to be made for the ear and tympanic bullae, which are of approximately the same size in the two subspecies.
"Mammals Obtained by Dr. Curt von Wedel from the Barrier Beach of Tamaulipas, Mexico"
E. Raymond Hall
He had a large tympanic membrane or "ear" on his ventral surface.
"Stamped Caution"
Raymond Zinke Gallun