OF THE TONGUES OF THE MAMMALIA, 283 



The apex is rounded, and bears many closely-aggregated conical 

 papillye, and a few small fungiform papillae. It has no notch. 

 The lateral horders are rounded and have the lateral organs at 

 their posterior extremities. The structures mentioned in the 

 introduction are absent. 



The Circitmvallate Papillce (text-figs. 17 A & 0). 



Three papillae form an equilateral triangle with the apex 

 behind. The two anterior papillae are smaller than the posterior 

 one, the fossae are all well-marked, and the Valiums appear as 

 clear zones. All are prominent, especially the posterior one, and 

 the surfaces are granular. 



Within the vallate triangle there are many large conical 

 papillae, and a fungiform papilla bisects the base. 



Several long sulci and laminae of the lateral organs convei^ge 

 towards the lateral vallate papillae and end on the outer borders of 

 the Valiums. In no other species of Gercopithecus is this condition 

 present. 



The Fungiform Papillce. 

 On the dorsal bounding fungiform zone the papillae have the 

 usual arrangement, as also on the sides and inferior surface. 

 They are hemispherical or bossed, and the surfaces are smooth or 

 granulai'o There is no distribution pattern according to size, and 

 the posterior rows are close together. One of them bisects the 

 base of the vallate triangle, 



The Conical Papillce. 



The papillae have the usual arrangement in clusters and rows 

 of diflferent degrees of obliquity. 



Appearance. — The papillae of the oral part are dark grey in 

 colour. All of them appear, to the naked eye, like small nodules. 

 Under a pocket lens they appear surrounded by zones of inter- 

 papillary dorsum (text-fig. 17 D), and have bodies of diflferent 

 shapes, with or without processes. 



Glands and Lymphoid N^ochdes. 

 Small nodules are present on the base, but no duct orifices are 

 visible. 



The Lateral Organs (text-fig. 17 0). 



The lateral organs begin anteriorly as a number of small ill- 

 defined fissures and laminae (text-fig. 17 0, a). These are followed 

 by a series of long tapering laminae and sulci (text-fig. 17 0, h) 

 converging towards, and ending on, the Valiums of the lateral 

 vallate papillae, and they are also convex forwai"ds. These are 

 succeeded by a number of laminae sepai-ated by sulci which are 

 all parallel to one another (text-fig. 17 0, c). Most of the 

 laminae are traversed by secondary sulci. The measurements, etc., 

 are shown as follows : — The right organ is 1"4 cm. long, and has 



Proc. Zool. Soc— 1921, No. XX. 20 



