22 DR. O. E. SONNTAG ON THE ANATOMY 



Both organs are convex inwardly and lie on the lateral borders, 

 with the inner extremities of their ridges and sulci on the dorsum. 

 In the specimen (No. J. 357.2, Mus, R.C.S.) which I examined 

 more of the left organ is on the dorsum, but that may be 

 produced by mechanical distortion. Most of the ridges are sub- 

 divided, and fungiform papillae invade the anterior ones on both 

 organs. Simple folds of the mucosa lie anterior to each organ, 

 and the lateral vallate papillae are level with the central laminae 

 and sulci. 



The following structures are absent : — 



1. Large lymphoid nodules with central pits. 



2. Lytta. 



3. Plicae fimbriatae. 



4. Apical gland of Nuhn. 



5. Foramen caecum. 



The frenuon is of moderate length. 



The ventral mesial sulcus is narrow, deep, and lodges an antero- 

 posterior crest. It runs back from the posterior border of the 

 papillary zone to the triangular depression into which the frenum 

 passes. 



The bifid sublingual fold is not present in the specimen in the 

 Museum of the Koyal College of Surgeons, and the frenum passes 

 straight from the triangular pit on the inferior surface of the 

 tongue to the mucous membrane of the floor of the mouth. 



The Bornean Gibbon (II. muelleri). 



The specimen described below was obtained from a female 

 Gibbon from Borneo which died in the Society's Menagerie. 



Measurements. — Total length 6'5 cm. ; length from the apex to 

 the central vallate papilla 5*25 cm. ; length from the central 

 vallate papilla to the epiglottis 1-25 cm.; width between the 

 attachments of the anterior faucial pillars to the edges of the 

 tongue 2-8 cm.; width of the apex 1-4 cm.; thickness at the 

 central vallate papilla r2 cm. ; thickness of the apex '6 cm. 



The tongue is, therefore, long and narrow, and it is pig- 

 mented. 



Pigmentation. — The dorsum in front of the vallate papillae is 

 bluish black in colour, and the glistening bluish-black fungifonu 

 papillae appear prominently on it, as their colour is darker than 

 the rest of the dorsum. The dorsum behind the vallate papillae 

 is not pigmented, is white, and the lateral organs lie at its antero- 

 lateral aspects, 



Tiie inferior surface has a central unpigmented area shaped 

 like the head of a spear, whose apex reaches the posterior border 

 of the papillary bounding zone. From the posterior extremity 

 of the hastate central area a narrow clear band runs on each side 

 to the lateral organ, and thus brings the clear areas of dorsum 



