OF THE TONGUES OP THE MAMMALIA. 27 



The mesial papillae are small, the vallum of the antei-ior papilla 

 consists of two crescentic ridges, and the vallum of the posterior 

 papilla is large and fusiform. 



The Fungifovm Papillce. 

 The fungiform papillae have the usual disposition in rows and 

 clusters. They tuberculate the apex. There are few on the 

 lateral borders, but they are numerous and prominent on the 

 anterior part of the papillary zone of the inferior surface. They 

 vary in prominence in different tongues, and the degree in which 

 they are concealed by conical papillae also varies. There is a 

 prominent cluster immediately in front of the vallate papillae, and 

 some invade the vallate Y and are hard to distinguish from 

 them. 



The Conical Papillce. 



Most of the conical papillae are of the filiform type, and have 

 the usual type of arrangement on the dorsum, lateral borders, and 

 inferior surface. Their points are directed backwards, or back- 

 wards and inwards, and they increase in size from before 

 backwards and without inwards. They conceal the anterior 

 fissures and ridges of the lateral organs. 



At the sides of, and posterior to, the vallate papillary Y they 

 become large and oval or round, with the apices directed back- 

 wards and inwards, and the round ones have each a long central 

 spine. 



The Lateral Organs. 

 Specimen 1 (text-fig. 8, R. & L.). 



Right organ : Length '8 cm. Ridges 5. Sulci 6. 

 Left organ : Length "8 cm. Ridges 4. Sulci 5, 



Specimen 2 (text- fig. 8). 



Right organ: Length 1"2 cm. Ridges 10. Sulci 11. 

 Left organ : Length I' 25 cva. Ridges 10. Sidci II. 



The lateral organs differ in character in the two specimens. 

 In specimen 1 there are six or five sulci appearing as slits 

 running obliquely forwards and upwards, and the intervening 

 laminae are coarse, short, and not greatly raised above the level of 

 the surface of the tongue. In the second specimen the organs 

 have the appearance usual in all the other Gibbons. 



The following structures are absent ; — 



1. Lymphoid nodules with- central pits. 



2. Lytta. 



3. Foramen caecum. 



4. Plicae fimbriatse. 



The sublingual fold is triangular in shape with a bifid apex. 

 From its upper surface the short frenum passes to the inferior 



