120 



DR. C. F. SONNTAG ON THE ANATOMY 



Tree Kangaroos it is anterior. When there are more than three 

 papill£e, they are arranged in chains, giving the appearance of the 

 letter Y, Y, T, orU. 



Structure. — Each papilla has a cylindrical or club-shaped body 

 rising from the bottom of a cylindrical depression, and the space 

 between the body of the papilla and the wall of the depression is 

 termed the fossa, the bottom of which is termed the fundus. 



The papilla may stand up higher than, be flush with, or 

 recessed below the surrounding dorsum, and the protruding 



Text-figure 10. 



\3 



The different macroscopic appearances presented by the circumvallate papillae. 

 Details in text. 



form is the commonest. When it is recessed, as in the Mono- 

 tremata and Marsupialia, the object attained is protection. 

 Poulton* showed how the vallate papilla of the Ornithorhynchus 

 consists of a ridge of delicate cells deeply recessed, and the vallum 

 cm contract over them to shelter them from noxious influences. 

 These variations are shown in text-fig. 10, nos. 1,2, 3. 



The fossa may appear as a mere slit round the papilla, or it 

 may be patulo'js, especially when the tongue is fresh. In the 

 Rhesus and Common Macaque Monkeys, the fossae of the two 

 lateral vallate papillae exhibit recesses at the anterior and 

 posterior papillary poles (text-fig. 10, no. 4). When the tongue 

 has been preserved these recesses close up, however. 



* Poulton, E. B., Proceeding-.s of tlu' Zoological Soci.etv of London, 1883, p. 599. 



