OF THE TONGUES OF THE MAMMALIA. 



303 



long, and has 4 laminae and 5 sulci. The dotted line in text- 

 fig. 41 C represents the margin of the unpigmented area round 

 the lateral organs. 



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

 delimited by a zone of large nodules with a. concave anterior 

 border. No duct orifices are visible even under a lens. 



The Frenal Lamella (text-fig. 41 B, a). — The large, flat, 

 triangular lamella covers a large area of the inferior surface of 

 the tongue, and is devoid of a ridge on its upper surface. The 

 apex is divided into small sharp processes, and the plain edges 

 extend back to the middle of the lateral organs. 



The Median Ventral Sidcus (text-fig. 41 B, h) lodges a well- 

 marked crest. It opens posteriorly into a flat, shallow, unpig- 

 mented triangular area. 



Text-figure 41. 



0LM/f 



The tongue of Ateles grisescens ; 1. 1. tonsils. 



The/renttm is very short. 



The ventral jjapillary harder is narrow, and its papillfe have 

 already been described. 



The Black-faced Spider Monkey {A. ater). 



Tuckerman (9) described the tongue, and the following 

 description is supplementary to his account. The measurements 

 of the larger of my two specimens are : — total length 4*9 cm. ; 

 length of the oral part 4-3 cm. ; length of pharyngeal part -6 cm. ; 

 wid'th between the lingual attachments of the palato -glossal folds 

 2 cm. 



The Gircumvallate PajnllcB (text-fig. 42 A & C).— Four large 

 papillae form a double-pair, and two small papilte lie on the. 



