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This study was carried out on a comprehensive collection of tongues of Pan troglodytes. Material of tongues of Tupaia glis, Microcebus murinus, Chirogaleus major, Lemur catta, Galago crassicaudatus, Cebus apella, and Macaca mulatta were used for comparison of the different stages of the development of the papilla foliata. The tongue of Pan exhibits longitudinal growth correlated with the growth of length of the jaws and individual age. A typical foramen caecum as it occurs in man was gross anatomically not recognizable. Seldom a small circular depression appeared in the midline close to the papilla circumvallata centralis which could be the remnant of the foramen caecum. There is a remarkable accumulation of papillae filiformes and fungiformes at the apex linguae; the same seems to be true for other genera of primates. It is self-explanatory that the accumulation of papillae makes the tip of the tongue a particularly sensitive area; this has been found to be true even in man. One specimen of the prenatal age just before term was studied. It exhibited remarkably elongated, thread-like papillae, their function is unknown as yet. They are no longer present in a newborn specimen of 4 d of age. In the aboral part of the dorsum linguae, a special kind of papillae occur; they are flat lobes which carry moderately elongated, tiny processes at their free margin. The function of these papillae is unknown; taste buds are absent.

This 2nd part of our studies shows that the papilla foliata is fully developed in Pan, Cebus, and Macaca; in Prosimians the papilla foliata is well developed in Lemur and Chirogaleus. In Galago crassicaudatus, this papilla is missing. Among 3 individuals of Microcebus, the papilla foliata was differently developed: in 2 cases, the tongue exhibited only 2 on both sides and a very low folia. Taste buds were found in the epithelium of only one side of each folium. In the 3rd case, the folia of the papilla were developed only on one side of the tongue, whereas, on the other side, a typical papilla was missing. Instead of the papilla, the tongue of the same animal exhibited a hillock-like structure; it is a gustatory hillock which exhibited many taste buds. There were 3 gustatory hillocks in all of the specimens of Tupaia glis; they are situated on both sides of the tongue.