The posterior wall of the otic capsule we have designated opisthotic in the figure.
"A New Order of Fishlike Amphibia From the Pennsylvanian of Kansas" by Theodore H. Eaton
Parietal bones separated by the supra-occipital; prootic and exoccipital separated by the enlarged opisthotic.
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 6" by Various
Here the opisthotic bone appears in the occipital region, as in the adult Chelonian.
"Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7" by Various
Opisthotic-exoccipital spur well-developed; epiplastral callosity, when present, not covering entire surface.
"North American Recent Soft-shelled Turtles (Family Trionychidae)" by Robert G. Webb