FIGURE 16 in A species level revision of Bridgerian and Uintan brontotheres (Mammalia, Perissodactyla) exclusive of Palaeosyops

FIGURE 16. Skull of Sphenocoelus hyognathus in ventral view illustrating the anatomy of the palatine and pterygoid regions. A, depression in palate marking probable original location of internal nares; B, actual location of internal nares (which are apparently closed off); C, apertures in pterygoid region at the termination of the nasal passage (functional internal nares). Choanal pouches shaded gray. Illustration based on AMNH 1851 (after Osborn, 1929) and AMNH 13164.