On the sublingual structures of Tarsius (Prosimiae, Tarsiiformes) and some platyrrhine monkeys (Platyrrhina, Simiae, Primates) with casual remarks on the histology of the tongue. In memoriam William Charles Osman Hill.

The sublingual structures of Tarsius, Cebuella and Callithrix are studied microscopically. Tarsius has a well developed but not specialized sublingua. In the platyrrhine monkeys the sublingua is lacking completely, but the frenal lamella (plica sublingualis) is very specialized. From this it is concluded that the sublingual organ of Callicebus is a topographically modified frenal lamella, not a sublingua.