SEM study on the dorsal lingual surface of the common tree shrew, Tupaia glis.

The dorsal lingual surface of the common tree shrew was examined by SEM after treating it with HCl to remove the mucous substance. Filiform (FI), fungiform (FU) and circumvallate papillae (CI) were observed. The FI exhibited a small circular bulge surrounded by anterior and posterior filamentous processes. FU were scattered among the FI. There were 3 CI separating the anterior 4/5 from the posterior 1/5 of the tongue. In addition, a group of conical projections with caudal orientation was found anterior to the palatoglossal fold on each side of the tongue. Microridges were widely observed on the entire dorsal lingual surface, except on the free surface of FI processes.