OP THE TONGUES OP THE MAMMALIA. 521 



Each is leaf -shaped, and has sevei'al hair-like processes along its 

 free edge, and all the points are directed backwards. Some of 

 the posteriar papillas may be umbilicated. They increase in size 

 in the usual manner. 



Lymjihoid Tissue and Glands.— The nodules form a naiTOW 

 zone in front of the epiglottis, but no duct orifices are visible, 

 even through the lens. 



77ie Lateral Organs. — The lateral organs consist of well-marked, 

 but small, backwardly -directed laminae separated by deep primary 

 sulci. The right organ has 3 laminae and 4 sulci, and the left 

 organ has 4 laminas and 5 sulci. 



The Inferior Surface (text-fig. 51 B, a & «"). — No ventral 

 papillary ::one is present, but the outer part of the inferior 

 surface incised by small fissures. 



The ventral mesial sulcus, which is narrow and deep, opens 

 posteriorly into a large triangular space. 



The frentnn is short, and the f renal lamella is triangular, Avith 

 a bifid apex, or a deep notched lateral border. 



Genus Mystax. 

 The ISTegro Tamarin (M. ursulus). 



My fresh specimen has the following measurements : — total 

 length 2-8 cm. : length of the oral part 2-4 cm. ; length of the 

 pharyngeal part -4 cm. ; width between the lingual attachments 

 of the palato-glossal folds 1'2 cm. 



The apex is rounded, and a dorsal median sulcus, which is more 

 marked thair in any specimen belonging to the Oercopithecidse, 

 Oebidae, or Hapalidse, runs back to the apex of the vallate triangle. 

 No transverse ridges or sulci are present. 



The Gircumvallate Papillm (text-fig. 52 A & C).— Four 

 papillae are arranged in the form of a V. Including the apical 

 papilla the right limb has three papillae and the left one has two. 

 The posterior papilla (A, a) is oval, with a well-marked fossa 

 and nodular vallum. The left lateral papilla (A, C h) lies in a 

 wide fossa with three small ones. The right lateral papilla 

 (A, C c) lies in a wide fossa with two small ones, and the right 

 mesial papilla is circular. 



The Fungiform Fapillct (text-fig. 52 A & B).~Small, but 

 well-marked papillae form a dorsal bounding zone, but the trans- 

 verse rows are maintained as far forwards as the apex. They 

 are absent from the inferior surface. 



The Conical Papillce, — No apical cluster is present, for the 

 papillae maintain their arrangement in rows right forward to the 

 apex, and there is no great increase in size from before-backwards, 

 or without-inwards. They have the usual arrangement on the 

 ventral papillary zone. All are cylindrical and surrounded by 

 zones of interpapillary dorsum. 



Lymphoid Tissue and Glands.— On each side of the epiglottis 

 there is a lara^e nodular mass, and the two are connected by a 



