OP THE TONGUES OF THE MAMMALIA. 315 



a posterior straight prolongation ; its vallum is prominent, 

 granular and coarsely nodulated. All the other papillae are small 

 and circular ; their bodies are smooth and polished, their fossae 

 are sharply cut, and their Valiums appear as clear zones. The 

 two small papillae on the left limb appear to stand on a common 

 vallum. 



Within the vallate area there are several large fungiform 

 papillae which can easily be mistaken for the small anterior vallate 

 papillae, but the pocket lens reveals how they have neither fossae 

 nor Valiums. The area is also considerably roughened by conical 

 papillae. 



The Fungiform Papillce (text-fig. 35). 



The fungiform papillae are absent from a small area on the 

 middle of the dorsum, but they have the usual arrangement 

 elsewhere. They are all hemispherical or bossed, and are 

 surrounded, but never concealed, by the conical papillae. 



The ventral apical cluster contains small elements. 



The Conical Papillce (text-fig. 35). 

 The conical papillae have the usual arrangement, and the usual 

 direction for their points. They have flat, cylindrical or tapering 

 bodies, and the number of points which each possesses varies. 

 Between the rows the interpapillary dorsum appears as strips. 

 The papillae on the base are prominent. 



Glands and Lymphoid Nodules. 



Several prominent elevations are formed on the base by 

 lymphoid nodules, and several orifices are present. These are 

 minute in front of the epiglottis, but there is, on each side of the 

 base of the tongue, a row of prominent round or slit-like orifices 

 stretching along the whole length of the palato -glossal folds. 

 These are more pronounced than in P. sphinx. 



The Lateral Organs (text- fig. 34). 



On each lateral border there is a series of short furrowed 

 laminae separated by wide sulci. The laminae do not project, 

 however. Some of the more posterior laminae appear as oval 

 bodies incised by deep secondary sulci, but these must not be 

 mistaken for glandular pits, from which they are separated by 

 a short interval. The right organ is 1-9 cm. long, and has 



11 laminae and 12 sulci. The left organ is 1*8 cm. long, and has 



12 laminae and 13 sulci. 



The Frenal Lamella (text-fig. 36). 



The lamella has a rounded, entire, finely crenated apex, .and 

 the edges, which are not prominent, extend almost as far back as 

 the middle of the lateral organs. 



Proc. Zool. Soc— 1921, No. XXII. 22 



