OF THK TONGUES OF THE MAMMALIA. 515 



clustei's and rows, but tlie apical cluster is small. Nowhere are 

 they numerous, however. They are absent from the inferior 

 surface. 



The Conical Pcqnllce are irregularly arranged, but they increase 

 in size in the usual manner and their points run in the usual 

 directions. They form a narrow papillary zone on the inferior 

 surface, but this is widest round the apex. 



Glands and Lymphoid Tissue. — The base of the tongue is finely 

 nodular, and a few oritices are visible when it is highly magnified. 



The Lateral Organs (text-fig. 48 C) form concave bodies on 

 the sides of the tongue, and the pointed or round laminae have 

 fungiform papillae below their bases. The lateral vallate papillae 

 are level with the centres of the organs. All rounded laminae 

 have wide secondary sulci. 



The right organ is 1 cm. long, and has 7 laminae and 8 sulci. 

 The left organ is -9 cm. long, and has 6 laminae and 7 sulci. 



The Lnferior Surface (text-fig. 48 B). — The ventral papillari/ 

 zone is narrow, the ventral median sulcus is shallow, and the 

 frenum is small. 



The jTrewaZ lamella is long and narroAv, and terminates in two 

 small points (text-fig. 48 B, a). 



Genus Alouatta ( = Mycetes). 

 The Black Howlek Monkey {A. caraya). 



The specimen had been preserved, so no measurements were 

 made. 



The Circumvallate PapiUce (text-fig. 49 A & 0). — Three 

 papillae form an isosceles triangle with long sides. The apical 

 papilla is far from the epiglottis, and the basal papilUe are close 

 to the lateral borders of the tongue. The length of the vallate 

 triangle is one-third the length of the dorsum. 



The apical papilla is large, oval, granular, and excavated in the 

 centre, the fossa is well-marked, and the vallum striated. 



The Fungiform Fapillce (text fig. 49 A & B) are not numerous, 

 but have the usual arrangement on the dorsum ; and a few lie at 

 the sides of the vallate triangle. They appear to stand on ridges 

 of the mucosa when the tongue is highly magnified. Those on 

 the inferior surface are very small. 



The Conical Papilke (text-fig. 49 A, B, & D), which are closely- 

 set, are irregularly disposed on the dorsum, but they increase in 

 size in the usual manner, and their points run in the usual 

 direction. They are filiform, cylindrical, or fusiform, and the 

 number of points to each papilla varies. Some stand up so 

 prominently round the fungiform ^^apillae that they conceal them 

 entirely. 



Glands and Lymphoid Tissue (text fig. 49 A). — The base of the 

 tongue is covered with nodules of various sizes, and many orifices 

 of ducts are visible to the naked eye. The lens reveals the 

 existence of many minute openings, and the base of the tongue is 



