10 DR. C. F. SONNTAG ON THE ANATOMY 



the Chimpanzee and Gibbons, in which most of the lateral 

 organs lie on the lateral borders of the tongue. 



Mesial Sulci. — Mesial sulci are present on the dorsal and 

 inferior surfaces. The dorsal sulcus lies in the centre of the 

 anterior two-thirds ; it is wide and shallow, and contains many 

 conical and few fungiform papillae. Just in front of the antero- 

 median vallate papilla there is a small pit containing both conical 

 and fungiform papillae, but this must be regarded as a part of the 

 mesial sulcus. It must not be mistaken for a foramen caecum, 

 which does not exist in the Gorilla. There is no median sulcus on 

 the base of the tongue. 



The median ventral sulcus (text-fig. 3 13, c) begins in front at 

 the posterior edge of the papillary zone and runs back, widening 

 as it goes, till it terminates in a triangular pit into which the 

 frenum passes. It lodges a median fold of mucous membrane 

 termed the plica mediana or mesial crest (text-fig. 3 B, d). 



Transverse Ridges and Sulci. — Several transverse ridges and 

 sulci are present on the anterior two-thirds of the dorsum. They 

 are undulating and irregular in direction, and some of them cut 

 the lateral borders of the tongue and run inwards on the 

 bounding papillary zone of the inferior surface. The sulci are 

 narrow and the ridges are covered with papillae. 



In the interior of the tongue there are neither lytta nor Apical 

 Gland of Nuhn. 



The Papillae. 



Pa/pillae are present on the entire dorsum, apex, lateral borders, 

 and a bounding zone on the inferior surface. The last is better 

 developed than in the Chimpanzee and Orang-Outan. 



The Circumvallate Papillai (text-tigs. 3 A & 3 D, a, b). 



In my specimen there are seven vallate papillae arranged in 

 the form of a Y, and the notable feature is that most of them 

 are compound. Each lateral limb has two papillae and the 

 median one has three. 



The two papillae of the right limb are compound (text- 

 fig. 3 D, a) and lie very close together, for their Valiums are only 

 separated from one another by a narrow fissure. Both fossae and 

 Valiums are prominent and the papillary elements are recessed 

 below the Valiums. The papillary bodies are granulated, possibly 

 as the result of secondary processes. 



The outer papilla of the left lateral limb (text-fig. 3 D, b) is 

 compound and the inner one is simple. The fossa? are patulous 

 and the two Valiums are in continuity. It seems as if the inner 

 papilla is an element which has been separated off from the outer 

 compound papilla. In the case of the compound papilla the 

 elements are recessed below the vallum, but the simple papilla is 

 more prominent. The surfaces of the elements are granular. 

 The outer papilla? of the lateral limbs are level with the 



